Diagnostic Services

Daily assays: As a guide most immunochemistry, indirect immunofluorescence, electrophoresis, cell markers and some neuroimmunology assays are carried out daily. Radial immunodiffusion (RIDs) though carried out on a daily basis take three days to completion.

Batched assays: Non urgent, expensive or labour intensive assays are batched and done on a weekly basis.

Urgent assays: Certain assays are available with a rapid turnaround time. These include ANA, dsDNA ab’s, glomerular basement membrane (GBM) ab’s, myeloperoxidase and proteinase 3 ab’s (ANCA). Specimens should be sent, or preferably brought, to the laboratory with the request form clearly marked “Urgent”. Prior warning for urgent requests is essential. It should be noted that urgent requests notably GBM and ANCA will be followed up with quantitative assays.

When sending specimens to the laboratory the following should be noted (for further information, please view our transport policy):

• Some complement components are labile. For these assays send 10ml of whole blood (for C3d use EDTA blood) immediately after venepuncture. For distant clinics the serum or plasma should be separated within the hour, frozen and sent to the laboratory to arrive frozen.
• For cryoglobulins whole blood should be taken using a warm syringe, transferred to a warm tube and brought to the laboratory whilst being maintained at body temperature. Prior warning that this test is required is appreciated.
• For Von Willebrand factor (FVIII Rag) use citrated tubes (4ml).
• Urinary free light chains (BJP). A 25ml aliquot of a random urine in a universal container (NO preservative) sent together with 10ml clotted blood.
• T cell antigen receptor & Immunoglobulin gene rearrangement studies: Please supply blood or bone marrow samples drawn into an EDTA bottle (N.B. Heparinised material may interfere with the PCR process).
• For all cell markers and cell functional assays please see the notes at the back of our book under ‘Cell Marker Tests’ and ‘Investigation of immune deficiencies’.
• T-SPOT TB: Two 7ml Lithium Heparin specimens are required for this
  assay. Samples must arrive in the laboratory before 2pm on the same day
  as they are drawn. This assay must be booked with laboratory staff before
  sending. Testing is only carried out Monday to Thursday. (Please note:
  samples sent on Fridays will NOT be processed).
• All high-risk specimens and accompanying form should be clearly labelled.

Please also note special requirements for cell work and neuroimmunology requests both of which have separate request forms.

Groups of tests which are useful in the diagnosis of patients with immunological disorders

Diagnosis of SLE:

Request ANA, dsDNA, ENA, C3/C4, GAM and CRP. For notes on SLE

Follow up of SLE:

Request dsDNA, C3/C4, CRP. (ANA, GAM and ENA at 3 monthly intervals.)

SLE in pregnancy or with imminent pregnancy:

These patients should also have their cardiolipin ab’s assayed.

Monitoring Infections:

Alternate day samples for CRP will give adequate information regarding response to antibacterial therapy. CRP, an acute phase protein, has a half life of 4-6 hrs.

Diagnosis of Myeloma: Full characterisation (Blood and Urine)

IgG, IgA, IgM, IgD; Immunofixation; B2M; Albumin, Total Protein, Densitometry, Cryoglobulin; Viscosity; Kappa and Lambda light chains and Creatinine.

Monitoring Myeloma: Follow up (Blood and Urine).

IgG, IgA, IgM or IgD; Electrophoresis; B2M; Kappa or Lambda light chains; Albumin, Total Protein, Densitometry, Creatinine.

Autoantibody screen:

ANA on Hep2 cells; GPC; LKM; AMA and SMA.

Arthritis screen:

ANA on Hep2 cells; CRP and RF.

Autoimmune/Viral liver disease:

SMA, AMA, LKM, IgG, IgA and IgM

Vasculitis screen:

ANA on Hep2 cells; ANCA and CRP.

Several laboratory tests may be useful in the diagnosis of clinical disorders involving inflammation of vessel walls. These include ANA, anti-neutrophil cytoplasmic antibody and measurement of immune complexes, Von Willebrand factor (FVIII Rag) and CRP. The laboratory offers a vasculitis screen of the three most commonly requested tests as first line investigation of this condition. The screen is aimed at cost reduction by laboratory efficiency compared to each assay being requested separately.

Vasculitis screen:

A vasculitis screen is available as an urgent request with a turnaround time of just two hours. However,since this disrupts the normal daily scheduled workload, there will be an additional but moderate charge for this service.