The enumeration of lymphocytes and their subsets and assessment of lymphocyte and neutrophil function in-vitro requires varying volumes of blood in plain tubes, EDTA-containing tubes and heparin-containing tubes. Sterile conditions also apply in some assays. Such investigations are not available without prior arrangements with the laboratory (please phone ext 42184).  Full details of specimens required will be given when tests are arranged. For lymphocyte surface markers in known HIV disease (CD3, CD4, CD8), 4mL of blood in EDTA should be taken and sent directly to the laboratory, which should be informed by telephone. Please contact the laboratory before taking the blood.

If you have any doubts about sample requirements, contact the laboratory for advice.

Specific IgE ("RAST")

Measurement of IgE to specified allergens can help to confirm allergies suspected on clinical grounds.  Results must be interpreted in the context of a detailed clinical history, and neither positive or negative results are diagnostic in isolation.  The allergens to be tested must be specified on the request.  This test is not suitable for broad "allergy screening" in the absence of a history suggestive of an allergic reaction.

Skin Prick Testing

In many cases skin prick testing provides a safe and simple alternative to specific IgE measurement, but this does require referral.

Referrals are accepted for the investigation and management of patients who have suffered anaphylaxis and patients with the the following allergic conditions:

Urticaria/Angio-oedema

Clear allergic precipitants can be identified in only a small proportion of cases.  Patients may respond well to regular treatment with antihistamines.

Food Allergy

Skin-prick testing for a range of food allergens is available.  "Screening" is not appropriate, and diet and symptom diaries often help to identify suspected foods for testing.  Patients with life-threatening reactions benefit from detailed advice and individualised management plans.

Allergic Rhinitis and Asthma

Skin prick testing can help to identify significant aeroallergens in these patients, which may held in planning medical management.  Pollen desensitisation may be offered under certain circumstances: patients will only be considered if adequate medical therapy has failed, and certain other suitability criteria are fulfilled. 

Bee/Wasp Venom Allergy

Assessment of patients who have suffered severe reactions to bee or wasp stings is offered.  In some cases desensitisation immunotherapy is indicated to prevent anaphylaxis in individuals at particular risk.

Antibiotic and Anaesthetic Allergies

Suspected antibiotic allergy (especially to penicillin) is common, and can usually be circumvented by the choice of an alternative antibiotic.  In exceptional circumstances allergy testing may be appropriate.  It is often important to exclude or identify allergy to local and general anaesthetic agents, so that future routine or emergency treatment can be given safely.  A detailed history of the suspected anaesthetic reaction and the anaesthetic agents used are vital to successful assessment. Testing of serum tryptase levels immediately after an anaphylactic episode often aids diagnosis (see Laboratory Services).

All clinical queries may be directed to a member of the medical staff. We are happy to assess in-patients following telephone arrangement. Out-patient referrals may be made, in writing, to Dr Huissoon. Urgent referrals should be discussed by telephone.

Blood tests to help in the investigations of these conditions are listed below and a guide to their use may be found in Test Profiles.

Connective Tissue Disease

This covers a wide range of relatively rare conditions including systemic lupus erythematosus (SLE), scleroderma, polymyositis and Sjorgren's syndrome.  Rheumatoid arthritis is common, and may present initially with similar features.  However, the early involvement of other organs (e.g. skin, kidneys, eyes, Raynaud's) may suggest an alternative diagnosis.

Vasculitis

Includes a heterogeneous group of diseases, characterised by inflammation and necrosis of blood vessel walls.  Presenting features may include fever, weight loss, fatigue, multi-system involvement (skin, nasal bleeding/crusting, arthralgia, myalgia, neuropathy), with raised inflammatory markers and abnormal urinalysis.  As with connective tissue disease, rapid diagnosis and treatment is essential to prevent organ damage and death. Serological markers such as ANCA may be helpful, but are not diagnositc and their absence does not exclude vasculitis.  Biopsy evidence of vasculitis is always preferable to confirm the clinical suspicion.

Clinical advice regarding the management of these conditions may be obtained from the department Medical Staff, or from the relevant clinical specialty (e.g. renal, medicine, rheumatology).  Patients may be referred to Immunology or to Rheumatology for assessment.

Advice for Medical Practitioners

Advice regarding the investigation, treatment or referral of all patients with possible connective tissue disease and vasculitis is available from the medical staff.  Advice out of normal working hours can be obtained from the on-call rheumatology, renal or medical teams (depending on the patient's particular problem).

Printed reports will be dispatched to the patient location when all requested tests have been reported and authorised. In the case of multiple requests on a single specimen, some results may be available prior to the issue of the written report. If you require any result, they may be available by telephone or via the Trust Intranet reporting module. The office staff will be able to give you the result or indicate when it is likely to be ready. Please mark all requests which are urgent as such and give clear details of where the result should be returned to. We endeavour to process all such requests as quickly as possible. The laboratory staff attempt to issue telephone results on all results deemed urgent.

If you have a query about any result or its interpretation, please telephone for assistance.

The basic approach to clinical problems is suggested.

The medical staff of the department are happy to advise with the investigation of any problems.

All tests should, if possible, be requested on the standard Immunology request form. Please take the extra time to furnish clinical details, registration data and hazard information. This assists quicker and safer processing and more accurate interpretation of laboratory data. If it is likely that the volume available at venepuncture will be limited, please contact the laboratory before phlebotomy to discuss the absolute minimum required to perform the requested tests.

Additional tests may also be performed on previously received specimens if sufficient is available in storage. Contact the laboratory by telephone to see if this is possible.