Flow cytometry

Introduction

All of the cells within the human body have specific physical properties such as size, complexity and surface markers. By analysing cells in the body to determine which markers are present, it is possible to distinguish different cell types from one another, even if under the microscope, they may look very similar.

A flow cytometer is used to do this, which, with the help of special reagents and dedicated software, can provide essential information on the type of cells present in a patient’s sample.

Although the physical properties of almost any cell in the body can be analysed by flow cytometry, we are primarily concerned with the blood cells found in the peripheral blood and bone marrow.

Laboratory testing times

Tests performed in the flow cytometry laboratory

CD4 count

This test is performed on patients who have been diagnosed with HIV to monitor the progress of their disease and their response to treatment.

Sample requirements

At least 0.5ml of fresh whole blood collected into a vacutainer containing potassium EDTA. Samples should be labelled with patient’s name, hospital number and date of birth. The sample should be kept at room temperature (avoiding direct sunlight, radiators etc) and is viable for up to 24 hours before being processed.

Turnaround times

Results can be expected to be available 24 to 48 hours from the sample being taken.

Rituximab monitoring (B cell count)

This test is used to monitor patients who are on rituximab for the treatment of rheumatoid arthritis or certain haematological diseases (as directed by a haematologist).

Sample requirements

At least 0.5ml of fresh whole blood collected into a vacutainer containing potassium EDTA. Samples should be labelled with patient’s name, hospital number and date of birth. The sample should be kept at room temperature (avoiding direct sunlight, radiators etc) and is viable for up to 24 hours before being processed.

Turnaround times

Results can be expected to be available 24 to 48 hours from the sample being taken.

HLA-B27 antigen

HLA-B27 antigen status can be used as a diagnostic indicator for several autoimmune and immune-mediated diseases including ankylosing spondylitis, reactive arthritis and anterior uveitis.

Sample requirements

At least 0.5ml of fresh whole blood collected into a vacutainer containing potassium EDTA. Samples should be labelled with patient’s name, hospital number and/or date of birth. The sample should be kept at room temperature (avoiding direct sunlight, radiators etc.) and is viable for up to 48 hours before being processed.

Turnaround times

Results can be expected 24 to 48 hours from receipt into the laboratory.

Referred tests

Leucocyte Immunophenotyping for leukaemia and lymphoma diagnosis (Cell Markers)

These are complex flow cytometry tests and are performed by the North East Haemato-oncology Diagnostic Service (NEHODS) in Newcastle.

Immunodeficiency

Testing for immunodeficiency is a very complex area.  If a diagnosis of primary immunodeficiency is suspected please contact the Immunology department at James Cook Hospital to discuss appropriate investigations:

Tel: 01642 854921

Alternative tel: 01642 854129