Flow Cytometry on Samples Other than Peripheral Blood

Department of Haematology

Notes

• Flow Cytometry tests are now carried out by North Bristol NHS Trust, so all samples are transported to Bristol.
• Flow Cytometry tests are usually performed on peripheral blood samples, but in certain instances it may be pertinent to perform these tests on other specimens such as bone marrow, cerebrospinal fluid or pleural fluid. Often, these samples are more precious and require processing more urgently and with smaller volumes than would usually be expected with peripheral blood. This page gives general guidance, but please always contact the laboratory directly to discuss specialist testing.
• This test would only be added onto a sample following discussion with a Consultant Haematologist. Please note, usually a fresh sample is required.

For information on specific flow cytometry tests, please see the following test pages:

• Acute / High Grade Immunophenotyping Panels
• Chronic / Low Grade Immunophenotyping Panels
• Lymphocyte Subsets

Bone Marrow

Immunophenotyping can be performed on bone marrow to aid the diagnosis of haematological diseases such as leukaemia.

Please collect bone marrow aspirate samples into EDTA, and mix well to avoid clotting.

Cerebrospinal Fluid

CSF samples are precious and cellular stability is greatly reduced in CSF when compared to blood samples. In addition, CSF samples usually require transport to a variety of departments for a variety of tests. This should be taken into account whenever taking CSF samples for pathological investigations.

The North Bristol NHS Trust Flow Cytometry department operates between 8.30am and 5pm Monday to Friday. However, where possible, CSF samples should be taken in the morning and not on a Friday. This is to allow time for transport and for the necessary tests to be processed. A sample received late on a Friday will not be suitable for testing by Monday morning.

If flow cytometry is required, you can contact the Department of Haematology in advance of sending the sample for any assistance.

Published studies show that, in health, CSF contains small numbers of white blood cells. Although a minimal CSF cell count is not universally defined, CSF can be expected to contain <5 white blood cells per µl (<30/µl in neonates). These are usually exclusively lymphocytes (predominantly CD4+ T lymphocytes with very low numbers of B lymphocytes and NK cells). In neonates, up to 60% of these cells may be neutrophils, with lymphocytes comprising the remaining 40%.

A CSF sample may be taken if there is a clinical suspicion of central nervous system infection, or infiltration by abnormal or leukaemic cells. If cells are present, the identification of the cells by immunophenotyping may be required.

Results must be interpreted carefully taking into account the CSF cell count and clinical details.

CSF samples for flow cytometry should, where possible, be collected into a clean universal container.

Pleural Fluid

Flow cytometry on pleural fluid is rarely required. Please contact the Department of Haematology to discuss what tests are required.

Turnaround Times

Please see the requisite Leukaemial / Lymphoma Immunophenotyping tests on the NBNHST test information web page.