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Immunology Services

Introduction

Analytical and consultative services are provided by the Immunology Department at Russells Hall Hospital, Dudley. Immunology test requests received are referred out to this service to assist clinicians with the diagnosis and management of their patients. Selection and interpretation of tests and the advisory service are provided by the Consultant Immunologist.

Consultant Immunologist:

Dr Malini Bhole, Russells Hall Hospital, Dudley, West Midlands, DY1 2HQ.
Secretary: Roz Turner (Telephone: 01384 244855).

Head BMS for Immunology:

Mr Mike Breese, Russells Hall Hospital, Dudley, West Midlands, DY1 2HQ.

Tel: 01384 244802

Requesting Tests

Requests can be made by either using the order comms system (ICE) or by completing a written request form. Samples should then be sent to the Central Specimen Reception, Pathology, Walsall Manor Hospital. Samples requiring immunology tests are then referred out the Immunology Department at Russells Hall Hospital, Dudley. Additional tests can usually be performed if required by contacting the laboratory. Please see appendix I for specialist tests that are available after discussion with a Consultant Immunologist.

Clinical Referrals

A written referral is required in line with the referral policy, addressed to Dr. Bhole. Requests for consultations can be made directly or by contacting the departmental secretary.

Specimen Collection

All tests require 5-10 ml clotted blood from adults unless otherwise stated (Appendix II). 

Full connective tissue disease screens and multiple allergy tests ideally require 10 ml. In instances where fresh clotted blood is required (e.g. complement assays), samples need to reach the laboratory within 2 hours of collection, clearly labelled for immediate separation.

For very young children, 1 ml is usually sufficient for a small number of tests e.g. ANA and rheumatoid factor. In the case of larger numbers of tests, please contact the laboratory before taking the sample as advice before hand may save the need for repeat venepuncture.

Specimen requirements for specialist Immunology requests.

Request

Specimen

Aquaporin 4 Antibody

(NMO Antibody)

Clotted

Basal Ganglia Antibody

Clotted

C1q

Clotted

Diptheria Antibody

Clotted

Histone Antibody

Clotted

Interferon Neutralising Antibody

Clotted

ISAC (CRD)

Clotted

MUSK Antibody

Clotted

Neuronal Antibody

Clotted

Meningococcal Antibody

Clotted

NMDA Antibody

Clotted

Ovarian Antibody

Clotted

Parathyroid Antibody

Clotted

Pneumococcal serotypes

Clotted

Testes Antibody

Clotted

Thyroglubulin Antibody

Clotted

Voltage Gated Calcium Channel Antibody

Clotted

Voltage Gated Potassium Channel Antibody

Clotted

C4 genotyping

EDTA x 2

MBL genotyping

EDTA x 2

The following tests need urgent handling:

After taking, the specimen should be sent to Pathology Specimen Reception as soon as possible.

Lymphocyte marker analysis and cell function studies require prior arrangement before the sample is taken.

Usually an EDTA sample is required for marker studies, but special tubes may be required for cell function. These samples will not be processed after 12.00 on Fridays as artefactual results may arise after weekend storage.

Results

If an urgent result is required e.g. GBM antibody screen, please contact the laboratory who will ensure appropriate results are available as soon as possible. The specimen must arrive in the laboratory by 12.00 to ensure same day results. Results, which are considered urgent are automatically telephoned to the requesting doctor if a bleep or contact number is supplied (the ward or consultant's secretary are notified otherwise).

Turnaround times

The turnaround times (TAT) of the high volume routine tests performed by the department are monitored and reported monthly as part of the key performance indicators for the department. The targets set are:

TEST

Target TAT

Immunoglobulins (IMM)*

4 hours

Rheumatoid Factor (RF)*

4 hours

Anti Nuclear Antibodies (ANA)

7 days

Anti Nuclear Cytoplasmic Antibodies (ANCA)

7 days

Cardiolipin Antibodies (CARD)

7 days

Smooth Muscle Antibodies (SMA)

7 days

Thyroid Peroxidase Antibodies (TPO)

4 days

Tissue Transglutaminase Antibodies (TTG)

7 days

*Analysis performed on the main Clinical Chemistry analyser

Results for tests referred to other laboratories, besides Russells Hall Hospital, will usually take more than 7 days to return and can take up to several weeks. Please enquire about results that appear to be delayed to ensure they have been correctly addressed for return.

 

 Immunology Tests:

 

Acetylcholine receptor antibody (ACR)

Reported as Negative or Positive (with a numerical result).

Normal range = 0-5 x10-10M

Positive in myasthenia gravis.

(Referred to Immunology dept, Churchill Hospital, Oxford)

Adrenal antibody

Reported as Negative or Positive.

Positive in the majority of cases of autoimmune Addison's Disease and in cases of autoimmune polyglandular endocrinopathies.

 (Referred to Immunology dept, Medical School, Birmingham)

Anti-Myelin Associated Glycoprotein (MAG) antibodies

Reported as Negative or Positive.

Anti-MAG can be found in certain sensori-motor neuropathies.

(Referred to Immunology dept, Medical School, Birmingham)

Anti-neutrophil cytoplasmic antibodies (ANCA)

Reported as Positive (and pattern) or Negative. ANCA positive samples are tested for MPO and PR3 by ELISA.

Cytoplasmic ANCA (cANCA) is a test for Wegner's Granulomatosis (80% of cases positive) and Microscopic Polyarteritis (20% of cases positive). Positives may occur in other vasculitic disorders such as SLE and Vasculitis associated with Rheumatoid Arthritis. Perinuclear ANCA (pANCA) is seen in Microscopic Polyarteritis, Churg-Strauss syndrome etc. Both cANCA and pANCA are also seen in some cases of bacterial infection (e.g. TB), some cases of rapidly progressive crescentic glomerulonephritis, vascular damage (e.g. MI, CVA) and inflammatory bowel disease (the latter often having an atypical pattern).

Turnaround time = 7 days

Anti-nuclear antibody (ANA)

Reported as Positive (titre and pattern) or Negative.

Over 95% of patients with SLE have a positive ANA result hence a negative result makes a diagnosis of SLE unlikely. The test is not specific for SLE as a positive ANA can occur in other conditions e.g. rheumatoid arthritis, systemic infections, other connective tissue diseases, chronic active hepatitis, juvenile arthritis, fibrosing alveolitis, and can be induced by drugs such as hydralazine and tetracyclines. Low titre ANA can also be found in the serum of many healthy elderly people. Different patterns of ANA are associated with different clinical conditions; this is reported where relevant. 

Turnaround time = 7 days

Aspergillus IgG (formerly 'precipitins')

Reported as positive or negative.

Positive results only indicate exposure and therefore not diagnostic in isolation. If a diagnosis of Allergic Bronchopulmonary Aspergillosis or aspergilloma has been made then a positive result is supportive of this. Usually done together with Specific IgE to Aspergillus fumigatus.

(Referred to Immunology dept, Medical School, Birmingham)

Avian IgG (formerly 'precipitins')

Reported as positive or negative.

Present in extrinsic allergic alveolitis caused by avian proteins.

(Referred to Immunology dept, Medical School, Birmingham)

NB These antibodies are found in at least 50% of people chronically exposed to the antigen but only a minority of these experiences clinical problems. Please discuss if the interpretation

of these results is in doubt. Only pigeon and budgerigar are available routinely.

Beta 2 Glycoprotein antibodies (B2 GPI)

Numerical result reported. Normal range = 0 - 20 EU/ml.

The ELISA used for cardiolipin antibodies detects B2 GPI antibodies concurrently. In cases of young adults with unexplained thrombotic episodes and no detectable cardiolipin antibodies or lupus anticoagulant, please contact the laboratory to discuss B2 GPI and IgM cardiolipin antibodies.

(Referred by arrangement only to Immunology dept, Medical School, Birmingham)

Beta 2 Microglobulin

Numerical result reported. Normal range: 0 - 4 mg/L.

Levels are raised with decreased renal function and in many B-cell tumours. This is one of the most important prognostic indicators in myeloma.

(Referred to Immunology dept, Medical School, Birmingham)

C1 Inhibitor

Requires prior discussion with the laboratory/consultants prior to sending sample.

Numerical result reported. Normal Range: 0.18 - 0.30 g/l.

Inherited or acquired defects of this protein usually result in severe angioedema, which is a painless, non-itchy swelling of sub-dermal tissues and is life-threatening if the larynx is affected. Low levels are found in 85% of cases of Hereditary Angioedema. The remaining 15% of cases are associated with a non-functioning protein, an assay for which is available. Normal C4 levels during an acute attack of angioedema virtually exclude C1-inhibitor deficiency. Acute attacks are treated by infusion of C1-inhibitor concentrate or Fresh Frozen Plasma. Clinical assessment by an Immunologist is strongly recommended where this diagnosis is suspected. Please note. C1-inhibitor deficiency is not associated with urticaria.

Fresh clotted blood should be taken.

(Referred to Immunology dept, Medical School, Birmingham)

 C3 Nephritic Factor

Requires prior discussion with the laboratory/consultants prior to sending sample.

Reported as Positive or Negative.

This IgG autoantibody stabilizes C3bBb and therefore results in continuous C3 breakdown. The presence of this autoantibody is associated with type II membrano-proliferative glomerulonephritis, with or without partial lipo-dystrophy and causes C3 levels to be very low.

Fresh clotted blood sample should be taken.

(Referred to Immunology dept, Medical School, Birmingham)

Cardiac Antibodies

Reported as Negative or Positive.

Found in Dressler's Syndrome, post cardiac surgery or in acute rheumatic fever but the diagnostic value of these antibodies is low.

(Referred to Immunology dept, Medical School, Birmingham)

Cardiolipin antibody (IgG)

Numerical result reported (* = IgG Phospholipid Units). Reported with interpretation.

Anti-Cardiolipin (ACL) and the Lupus Anticoagulant are members of a family of anti-phospholipid antibodies. Some patients with SLE have modest levels of these antibodies but the most striking associations are with thrombotic episodes and recurrent foetal loss. As the syndromes associated with ACL are treatable, it is appropriate to seek its presence in the following groups of patients:

  • Women with recurrent unexplained foetal loss.
  • Young patients with stroke, myocardial infarction or transient ischaemic attacks, without other predisposing factors.
  • Young patients with recurrent venous or arterial thromboses.
  • Patients with unexplained thrombocytopenia.
  • Patients with SLE for assessment of thrombotic risk in pregnancy.

Clinical details are essential for the accurate interpretation of the result.

B2 GPI antibodies are detected in addition to ACL in the assay used. This test can be arranged separately if required for specific patients.

NB. Lupus anti-coagulant testing is performed in Haematology; please send a minimum of 2 x 2.5 ml citrated blood and state if the patient is on anticoagulant treatment and if so, which one.

Turnaround time = 7 days

Cardiolipin antibody (IgM)

Numerical result reported (* = IgG Phospholipid Units). Reported with interpretation.

Less specific than IgG cardiolipin, but high titres can be seen in anti-phospholipid syndrome (APS)

Turnaround time = 7 days

Centromere antibody

Reported as ANA positive or negative.

Usually found in CREST variant of scleroderma (limited scleroderma). Patients with severe Raynaud's and other features of scleroderma, especially lung and other organ involvement, should also be screened for Scl-70, which is associated with systemic sclerosis.

Turnaround time = ~7 days for screen

CH50/APH50

Requires prior discussion with the laboratory/consultant prior to sending sample.

Numerical result reported with interpretation.

Functional tests of classical and alternative complement pathways. Very low levels occur if any component is absent. Any patient with meningococcal disease or severe sepsis should be screened with a CH50/APH50 during convalescence. CH50 is not suitable for the routine monitoring of patients with SLE. Please seek the advice from the department if you are not fully conversant with these tests.  

Clotted sample required by laboratory within 2 hours of venepuncture: please advise laboratory of expected sample.

(Referred to Immunology dept, Heartlands Hospital, Birmingham)

Complement components C3 and C4

Numerical result reported.

Normal Range:  C3 0.75 - 1.75 g/l

                          C4 0.14 - 0.54 g/l

Blood must be taken as atraumatically as is practical and reach the laboratory as soon as possible in order to avoid artefactual breakdown of components.  C3/C4 levels are useful in monitoring conditions associated with immune complexes e.g. SLE, systemic vasculitis, SBE. A decrease, primarily of C3, can be associated with gram negative bacteraemias and post-streptococcal GN. A profound decrease in C3 should alert the clinician to the possibility of a C3 nephritic factor (see above). Low C4 levels can be found in individuals with a C4 null allele (these people have an increased risk of developing SLE) and in cases of active connective tissue disease.  An isolated decrease in C4, associated with angioedema, suggests C1-inh deficiency whereas a low C4 with renal disease and/or vasculitic rash suggests the presence of a cryoglobulin. Increased production can maintain normal levels even if consumption is rapid.

Turnaround time = 24 hours

Cryoglobulins

It is important the laboratory is contacted before collection of a specimen for this assay.

Reported as positive or negative, positives are sent to for typing.

When cryoglobulins are associated with Waldenstroms macroglobulinaemia, myeloma or lymphoma they consist of one immunoglobulin isotype but may be mixed or polyclonal in other diseases such as connective tissue disease. Patients with renal disease and a low C4 level or patients with unexplained cutaneous vasculitis should be screened for the presence of circulating cryoglobulins.

Cyclic Citrullinated Peptide (CCP) antibodies                                                     

Numerical result reported with interpretation.

Found mainly in Rheumatoid arthritis and more specific than rheumatoid factor with approximately the same sensitivity. Diagnostically useful in acute arthritis, enabling rapid initiation of DMARD therapy but we strongly recommend use in acute arthritis

clinic rather than primary care. Patients with acute of arthritis of more than 3 week's duration should be referred to an acute arthritis clinic.

(Referred to Immunology dept, Dudley)

DNA antibodies

Reported as Positive or Negative screen then numerical value by ELISA performed. Interpretation given on the report.

This test is confirmatory for most patients with SLE. Only double-stranded antibodies are detected and positive/strong positive results are diagnostic for SLE until proved otherwise. Only 60% of all patients with SLE have these antibodies in their serum hence a negative test does not exclude the diagnosis.  Occasionally DNA antibodies may be found in patients with autoimmune chronic active hepatitis. The circulating half-life of IgG means that levels may not be that useful for monitoring disease activity on a short term basis; C3 and C4 levels provide a more useful guide.

Turnaround time = 7 days for screen.

Endomysial Antibodies

Reported as Positive or Negative.

This test is only performed if the IgA Tissue Transglutaminase (TTG) antibody is positive.

So far these antibodies have only been found in cases of coeliac disease / dermatitis herpetiformis and provide a specific test for these conditions. The test will be negative in patients with coeliac disease and IgA deficiency. For these reasons IgG deamidated gliadin assays are available.

Turnaround time = 10 days

Epidermal Antibodies

Reported as Positive (desmosome or basement membrane) or Negative.

Circulating antibodies to epidermal desmosomes are present in the majority of cases of pemphigus and antibodies reactive with the basement membrane are found in cases of pemphigoid, epidermolysis bullosa aquisita and a minority of cases of herpes gestationis.

Turnaround time = 7 days

Extractable Nuclear Antigens (ENA)

Reported as Positive or Negative and typed if positive.

These antibodies generally give rise to speckled ANAs and recognise cellular antigens extracted by saline. Antibodies to ENAs are found in various connective tissue conditions as listed below. Patients with SLE or Sjögren's should be screened for ENA antibodies if considering pregnancy. Repeated testing for ENA is not indicated unless there is a change in symptoms. Levels do not indicate disease activity.

Ro (SSA):      Sjögren's Syndrome (SS), SLE, congenital heart block, neonatal lupus, RA.

La (SSB) :      SS, SLE, RA.

RNP:               Mixed Connective Tissue Disease, SLE.

Sm:                 SLE.

Scl-70:            Scleroderma.

Jo-1:               Myositis, particularly with interstitial lung fibrosis.   

The absence of an antibody does not exclude a clinical diagnosis, as ENAs are present only in a variable proportion of patients with the above disorders.

Turnaround time = 7 days for ENA screen; approximately 14 days for ENA characterisation.

Functional Antibodies (FAB)

Antibody levels reported as units/ml. Interpretation supplied with results.

Measurement of isotype-specific antibodies to tetanus toxoid, Strep. pneumoniae, and H.influenzae type b are available. These antibodies are protective and levels can be enhanced by immunization. The assays are of value in investigating:

  • Patients, especially children, with recurrent bacterial sepsis; particularly of the upper and lower respiratory tract.
  • Patients with invasive disease caused by the encapsulated organisms listed above.
  • Patients undergoing splenectomy or having haemoglobinopathies.
  • Patients with antibody deficiency states and in monitoring immunoglobulin replacement therapy.
  • Immune reconstitution following BMT.

Interpretation of results and suggested follow up action, e.g. immunization with a relevant vaccine, is given on the report. Detailed clinical information and the patient's age are essential for the interpretation of results.

Functional C1 Inhibitor

Requires prior discussion with the laboratory/consultant prior to sending sample.
Inherited or acquired defects of this protein usually result in severe angioedema, which is a painless, non-itchy swelling of sub-dermal tissues and is life-threatening if the larynx is affected. Low levels are found in 85% of cases of Hereditary Angioedema. The remaining 15% of cases are associated with a non-functioning protein, and the functional assay is available to measure this. Acute attacks are treated by infusion of C1-inh concentrate or

Fresh Frozen Plasma. Clinical assessment by an Immunologist is strongly recommended where this diagnosis is suspected.

Clotted sample required by laboratory within 2 hours of venepuncture: please advise laboratory of expected sample.

(Referred to Immunology dept, Heartland’s Hospital, Birmingham)

Ganglioside Antibodies

Reported as Positive (titre) or Negative.

A range of lower motor neuron neuropathies can be associated with the above.

(Referred to Immunology dept, Medical School, Birmingham)

Gastric Parietal Cell Antibodies (GPC)

Reported as positive or negative.

GPC antibodies have a strong association with pernicious anaemia and autoimmune gastritis.  Low titres are commonly found in normal elderly females. If positive, testing for Intrinsic Factor antibodies will be carried out.

Turnaround time = 7 days

Glomerular basement membrane (GBM) antibody

Reported as positive or negative. Interpretation provided on the report.

Positive in Goodpasture's syndrome/anti-GBM disease.Contact the laboratory if an urgent result is required. Immunofluorescence of a renal biopsy is the suggested method of diagnosing anti-GBM disease in patients with rapidly progressive glomerulonephritis.

Turnaround time of screen = approximately 7 days

(Any equivocal, weak positives and positives are sent of for further testing).

Glutamic Acid Decarboxylase Antibodies (GAD)

Numerical result reported with interpretation.

GAD can help to differentiate Latent Autoimmune Diabetes in Adults from Type 2 diabetes and gestational diabetes and for risk prediction in immediate family members for Type 1. GAD antibodies are also seen in Stiff Man Syndrome.

(Referred to Immunology dept, Medical School, Birmingham)

Immunoglobulins/Serum protein electrophoresis

Age related normal ranges given with report.                   

Paediatric ranges given where appropriate.

Essential investigation for 'failure to thrive', recurrent infections and lymphoproliferative diseases including myeloma.

Polyclonally raised IgG can be a feature of chronic infections (notably HIV, TB and trypanosomiasis), connective tissue disease or liver disease.

Polyclonally raised IgA is also found in late stage HIV infection but more commonly associated with liver disease, especially alcoholic in origin.

Low levels always warrant further investigation as serious infective complications can occur. Reduced levels are found in many primary immunodeficiencies but secondary causes (e.g. nephrotic syndrome, lymphoproliferative disorders, and protein-losing enteropathy) are more common, especially in adults. IgA deficiency occurs in 1 in 800 of the population and may not be associated with disease (but can lead to reactions to blood and blood products). All cases of suspected primary immunodeficiency should be discussed with Consultant Immunologist in order that comprehensive investigations can be arranged. 

Turnaround time 4 hours for immunoglobulins, 7 days for serum electrophoresis.

IgE (total)

Numerical result reported (KU/L).

Age related normal ranges given with report.

Total IgE may be helpful in diagnosing atopic disease. Total IgE levels may not be elevated even if specific levels are raised. IgE can also be raised in asthma, eczema, parasitic infestations, lymphoma, liver disease and the rare Hyper-IgE syndrome. Raised total IgE is not helpful in diagnosing type I IgE mediated allergy. Specific IgE tesing is more useful.

See Specific IgE testing.

Turnaround time = approximately 4 hours.

IgG subclasses

Numerical result reported (g/L). Age related normal ranges given with report.

Measured in cases of suspected antibody deficiency such as patients with recurrent respiratory infections and in cases of severe infection by encapsulated bacteria. Functional antibody levels should also be performed on these patients. Low sub-class levels may not be reflected in low levels of total IgG.

Intrinsic Factor (IF) Antibodies.

Reported as a value with interpretation.

Present in the majority of patients with pernicious anaemia. The presence of IF antibodies virtually excludes other causes of vitamin B12 deficiency. IF antibodies are very rarely found in the absence of GPC antibodies and will not be tested for in GPC negative patients unless B12 deficiency has been demonstrated. IF antibodies are not indicated if the Vitamin B12 level is not low.

(Referred to Immunology dept, Dudley)

Leukocyte Marker Studies

Report with results.

The principal indications for these tests are haematological malignancy and immunodeficiency either primary or secondary (including known HIV infection). The range of available markers is extensive so it is essential to give as much clinical detail as possible in order that appropriate analysis is performed. Requests for the investigation of haematological malignancy should be addressed to Haematology whilst those for immunodeficiency must be arranged through the Immunology Department.

WBC and differential should be performed at on the same day, as this is essential for correct reporting. An EDTA sample is usually required.

These tests cannot be analysed after 12.00 on Friday as storage can give artefactual results.

(Referred to Immunology dept, Medical School, Birmingham)

Lymphocyte Function Analysis

Report with results.

Tests of lymphocyte function are available in cases of suspected primary immunodeficiency on discussion with consultant Immunologist in the Immunology Department. These tests are particularly relevant in cases of recurrent viral or fungal infection, which are not associated with an overt cause such as HIV infection.

These tests can only be performed by prior arrangement and collection details will be given at this time.

(Referred to Immunology dept, Medical School, Birmingham)

Mast Cell Tryptase

Numerical result reported. Normal range: 2 - 14 mg/l.

This enzyme is released from mast cells during anaphylactic and anaphylactoid reactions. It remains stable after venepuncture. Levels peak at around 6 hours after a reaction and return to normal within 24 hours. Raised basal levels suggest systemic mastocytosis. See Investigation of anaesthetic reactions.

(Referred to Immunology dept, Dudley Hospital)

Mitochondrial Antibodies (AMA)

Reported as Positive or Negative.

Present in the vast majority of patients with Primary Biliary Cirrhosis and commonly associated with a polyclonal elevation in IgM. Also seen in connective tissue disease e.g., Sjogren's Syndrome, scleroderma, and rheumatoid arthritis.

Turnaround time = 7 days

Myeloperoxidase Antibodies

Numerical result reported. Negative <3 iu/ml, Equivocal 3.5 - 5, Positive >5.

Found in MPA, Churg- Strauss syndrome and infrequently in Wegner's Granulomatosis and some other systemic vasculitides.

(Referred to Immunology dept, Dudley Hospital)

Neutrophil Function Analysis

These tests are useful in diagnosing uncommon primary neutrophil defects that usually present in childhood with recurrent deep-seated bacterial or fungal infections and poor wound healing.  These tests can only be performed after prior arrangement with the department.

(Referred to Immunology dept, Medical School, Birmingham)

Oligoclonal Banding

Restricted IgG bands are seen in the CSF of cases of multiple sclerosis, neurosarcoidosis, syphilis, SSPE and CNS lymphoma but not in serum. IgG bands can also be seen in SLE hence a serum sample is required to run in parallel as in SLE bands are present in serum and CSF.

(Referred to Immunology dept, Medical School, Birmingham)

Pancreatic Islet Cell Antibodies

Reported as Positive and Negative.

Usually present in type I diabetes mellitus at presentation but their main use is in predicting IDDM in siblings of affected patients. The persistence of these antibodies is often found in diabetes mellitus that is associated with polyendocrine disease.

(Referred to Immunology dept, Medical School, Birmingham)

Paraneoplastic antibodies

Reported as Positive (titre) or Negative.

A range of autoantibodies that can be seen in neurological conditions associated with neoplasia are available. Advice from a consultant neurologist should guide testing.

(Referred to Immunology dept, Medical School, Birmingham)

Paraprotein Measurement

Performed by the Immunology Department at Dudley. Please send a clotted blood for analysis.

Paraproteins are detected on electrophoresis of serum and are found in most cases of myeloma and some cases of other B-cell tumours. They can also arise in immunocompromised patients in instances of infection. Low levels of paraprotein are seen in up to 20% of patients over the age of 75 years. Measurement is useful for monitoring the treatment of myeloma and other lymphoid malignancy where a paraprotein is present. For the diagnosis of myeloma, blood and urine samples must be sent.

PR3

Numerical result given. Negative <2, Equivocal 2-3, Positive >3 IU/ml.

PR3 antibody is a marker for Wegener's granulomatosis and is occasionally detected in microscopic polyarteritis. The quantity of PR3 antibody is generally parallel to disease activity.

(Referred to Immunology Dept, Dudley Hospital)

Specific IgE TESTS

Reported in units (kU/L) and Graded 0 (Negative) and 1-6 (Positive).

Specific IgE tests are available for a wide range of allergens, but must be interpreted in light of the history. Clinical details and suspected allergens must be stated on the request.

In cases of drug sensitivity (e.g. antibiotic, anaesthetic agents) it is advisable to discuss the case with the Consultant. Specific IgE to penicillin is very specific and therefore is suggestive of penicillin allergy when positive. It is, however, not very sensitive and therefore may be negative in truly allergic individuals.

ON NO ACCOUNT SHOULD A CLINICAL CHALLENGE WITH AN AGENT SUSPECTED OF CAUSING ANAPHYLAXIS BE UNDERTAKEN WITHOUT FULL RESUSCITATION EQUIPMENT AND TRAINED STAFF AT HAND.

(Referred to Immunology dept, Dudley Hospital)

Rheumatoid Factor (RF)

Numerical result reported. Normal <20 IU/mL.

Only >40 is likely to be significant.

In Rheumatoid Arthritis, the presence of a high titre RF at onset is of some predictive value as these patients have a worse prognosis than seronegative patients. Low titres may be found in normal elderly people and in cases of viral infection, chronic bacterial infections, connective tissue disease, and lymphoproliferative disorders and are of low diagnostic value. This test is of no value in monitoring RA. A negative test for RF can be helpful in the differential diagnosis of rheumatic diseases as they are not usually detected in rheumatic fever, gout, Reiter's syndrome, ankylosing spondylitis, osteoarthritis, psoriatic arthritis and Juvenile Chronic Arthritis.

Turnaround time = ~4 hours.

Salivary Gland Antibodies

Not available: ENA antibodies are a more sensitive test for Sjögren's Syndrome.

Smooth Muscle Antibodies (SMA)

Reported as Positive or Negative.

Present in up to 75% of cases of autoimmune chronic active hepatitis. Low titre antibodies are found in a few patients with other liver diseases such as viral hepatitis, cholelithiasis and in infections.

Turnaround time = 7 days

Striated Muscle Antibodies

Not available: Acetylcholine receptor antibodies are a more specific and sensitive test for myasthenia gravis.

Thyroid Peroxidase (TPO) Antibodies

Numerical result reported. Normal <34 IU/ml.
Present almost exclusively in cases of autoimmune thyroid disease (Grave's disease, Hashimoto's thyroiditis and primary myxoedema). These antibodies can be present without overt thyroid dysfunction in cases of autoimmune polyendocrine disease.

Turnaround time = 4 days.

Tissue Transglutaminase (IgA) Antibodies (TTG)

Numerical result reported.

Negative <7 U/ml

Equivocal 7-10 U/ml

Positive >10 U/ml

Tissue transglutaminase is the major autoantigen in coeliac disease. IgA antibodies against TTG are highly disease specific serological markers for coeliac disease and dermatitis herpetiformis. The test will be negative in patients with coeliac disease and IgA deficiency. For these reasons IgG gliadin antibodies are available on specific request. Weak levels without associated endomysial antibodies are seen in liver disease.

Positive TTG results will be confirmed with the anti-endomysial antibody test.

Turnaround time = 7 days

Tissue Transglutaminase (IgG) Antibodies

Numerical result reported with interpretation.

This assay can be used in patients who are IgA deficient and where coeliac disease is suspected. In cases where the Total IgA level is <0.05 g/l, the IgA TTG test can be negative and an IgG TTG test is suggested.

This test is only available when specifically requested.

(Referred to Immunology Dept, Dudley Hospital)

Urine Electrophoresis

Reported as normal or abnormality described.

Used to detect urinary free monoclonal light chain associated with myeloma and some cases of lymphoma. Polyclonal free light chains may occur in the urine of healthy normal individuals and in patients with chronic infections or inflammatory disease such as Rheumatoid Arthritis.  

(Referred to Immunology Dept, Russel's Hall Hospital, Dudley)

Suggested test profiles for particular conditions

Medical and laboratory staff are always happy to discuss suitable tests for various circumstances. Given below are some recommended test profiles that can be of help in diagnosing or excluding the listed conditions. All cases of suspected primary immunodeficiency, angioedema and anaphylaxis should be discussed with the consultant.

 Diagnosis of Immunodeficiency

The pattern of infections provides the largest degree of help in diagnosing immunodeficiency:

Bacterial infections, particularly with encapsulated organisms, suggest antibody or complement deficiency. Useful initial investigations are Immunoglobulins, FAB, CH50.

Viral and/or fungal infections suggest a T cell abnormality. Useful initial investigations are a lymphocyte count, Immunoglobulinss, FAB. Lymphocyte function tests and surface markers are required to fully assess T cell immunity and are available only by prior arrangement with Consultant Immunologist.

Staphylococcal skin sepsis, deep-seated fungal infections, poor wound healing and severe periodontal problems suggest a neutrophil abnormality. Neutrophil function tests and surface marker analysis are required to fully assess neutrophil activity and are available only by prior arrangement.

Diagnosis of SLE and other connective tissue disorders

SLE should be considered as a potential cause of symptoms such as small joint arthropathy and rashes or symptoms of serositis (e.g. unexplained pleuritic chest pain, mouth ulcers). Useful initial investigations are ANA, RHF, and ESR. Patients with a significantly positive ANA will automatically be screened for DNA and ENA antibodies. It is recommended that the advice of a Consultant Rheumatologist be sought in cases where a connective tissue disorder is suspected.

Women with SLE who are or are likely to become pregnant should be checked for Cardiolipin antibodies, Ro (SSA) antibodies and La (SSB) antibodies.

Monitoring of patients with SLE:

Tests that are of use in monitoring patients with SLE include ESR, C3, C4 and DNA as well as FBC and renal function assessment.

Investigation of renal failure

Immunological investigations of value in assessing patients with renal failure include ANA, C3, C4, Igs, CRP, cryoglobulins and ANCA if the cause is not apparent. Other tests available are GBM antibodies and C3 nephritic factor (the latter is indicated in cases of a low C3).

Investigation of severe angioedema

It is advisable to seek clinical assessment by an Immunologist in all cases of severe angioedema. C1 inhibitor deficiency needs to be excluded by testing for C1 inhibitor and C4 levels. Severe urticaria is never associated with C1-inh deficiency and only associated with raised IgE levels in a minority of cases. Type I ACE inhibitors are a well recognized cause of angioedema.

Investigation of vasculitis

If a diagnosis of vasculitis is suspected then it is advisable to ask for a clinical assessment by a physician experienced in managing this group of disorders. Laboratory investigations are of limited value in arriving at a diagnosis but investigations which may be of some use include CRP, ANCA, ANA, RF, C3, C4, Immunoglobulins, and cryoglobulins.

Allergy Testing and Specific IgE

The department offers a skin prick testing service for common inhalant and food allergies by appointment on Mondays. Appointments can be made by contacting the laboratory directly or sending in a referral. An appointment will then be sent out to the patient.

Specimens may be taken for total IgE and Specific IgE if it is felt that this is indicated from the results of the skin prick test.

NB: If a request for Specific IgE tests is received by the department without prior skin prick testing the specimen will be separated and divided into two aliquots, one of which will be analysed for total IgE and the other stored at -70°C, to await the result. The Specific IgE is an expensive investigation and can produce false positive results at high total IgE levels. If the total IgE level is >2000 IU/ml the patient can be considered atopic.  An IgE >2000 IU/ml may lead to false positive results and should be viewed with caution.

Specialist Tests

Specialist tests are expensive and are only available after discussion with a Consultant from the relative specialty.

Neurology:

  • Aquaporin 4 Abs (or 'NMO' Abs)
  • Basal Ganglia Antibody
  • Interferon Neutralising Antibody
  • MUSK Antibody
  • Neuronal Antibody
  • NMDA Antibody
  • Voltage Gated Calcium Channel Antibody
  • Voltage Gated Potassium Channel Antibody

Immunology:

  • C1q
  • C4 genotyping
  • Diptheria Antibody
  • ISAC (CRD):
  • IgE testing against an array of purified allergens is available when history and conventional IgE testing does not provide sufficient information for patient management eg there is no history of recent exposure to suspected allergic triggers. This test is available with prior discussion with a Consultant Immunologist and will be charged to the appropriate directorate.
  • Lymphocyte surface markers
  • MBL genotyping
  • Meningococcal Antibody
  • Neutrophil function tests
  • Pneumococcal serotypes

Metabolic Medicine:

  • Ovarian Antibody
  • Parathyroid Antibody
  • Testes Antibody
  • Thyroglubulin Antibody

Miscellaneous:

  • Histone Antibody

Specimen requirements for specialist Immunology requests.

Request

Specimen

Aquaporin 4 Antibody

(NMO Antibody)

Clotted

Basal Ganglia Antibody

Clotted

C1q

Clotted

Diptheria Antibody

Clotted

Histone Antibody

Clotted

Interferon Neutralising Antibody

Clotted

ISAC (CRD)

Clotted

MUSK Antibody

Clotted

Neuronal Antibody

Clotted

Meningococcal Antibody

Clotted

NMDA Antibody

Clotted

Ovarian Antibody

Clotted

Parathyroid Antibody

Clotted

Pneumococcal serotypes

Clotted

Testes Antibody

Clotted

Thyroglubulin Antibody

Clotted

Voltage Gated Calcium Channel Antibody

Clotted

Voltage Gated Potassium Channel Antibody

Clotted

C4 genotyping

EDTA x 2

MBL genotyping

EDTA x 2

The below tests need urgent handling:

After taking the specimen it should be sent to Pathology Specimen Reception as soon as possible.

On receipt, the specimen should go directly for analysis.

Lymphocyte surface markers

(CD3/CD4CD8, LFA markers etc)

(B, NK, memory markers etc)

EDTA x 2

Lymphocyte proliferation test

(Lymphocyte stimulation/ function)

Lithium

Heparin

Neutrophil function tests

(Respiratory burst)

Lithium

Heparin

CH50/APH50

Clotted (frozen immediately after separation)

C1 inhibitor function

Clotted (frozen immediately after separation)

 

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