Full Blood Count (FBC)

Department of Haematology

Notes

• Full blood counts are performed on automated equipment and provide haemoglobin concentration, red cell indices, white cell count (with a differential count) and platelet count.
• The presence of abnormal white cell and red cell morphology is flagged by the analysers.
• Blood films may be inspected to confirm and interpret abnormalities identified by the cell counter, or to look for certain specific haematological abnormalities.
• Grossly abnormal FBC results and abnormal blood films will be phoned through to the requestor.
• There is no need to request a blood film to obtain a differential white count. It is, however, important that clinical details are provided to allow the laboratory to decide whether a blood film, in addition to the automated analysis, is required.
• Under some circumstances a differential is not routinely performed, e.g. pre-op, post-op, antenatal and postnatal requests.
• Full Blood Counts are performed at CGH and GRH
• See also: Reticulocyte Count

The FBC comprises the following tests

Standard

• Haemoglobin (Hb)
• White Blood Count (WBC)
• Platelet Count (Plt)
• Red Cell Count (RBC)
• Haematocrit (HCT)
• Mean Cell Volume - Red cell (MCV)
• Mean Cell Haemoglobin (MCH)

Differential White Cell Count (where applicable)

• Neutrophils
• Lymphocytes
• Monocytes
• Eosinophils
• Basophils

And if appropriate

• Blood Film

Sample Requirements

2ml or 4ml EDTA sample or a Paediatric 1ml EDTA sample.

Sample Storage and Retention

• Pre analysis storage: do not store, send to laboratory within 4 hours.
• Sample retention by lab: EDTA samples are retained for a minimum of 48 hours at 2-8°C
• Transport of samples may affect sample viability, i.e. FBC results will degenerate if exposed to high temperatures, such as prolonged transportation in a hot car in summer.

This test can be added on to a previous request as long as there is sufficient sample remaining and the sample is less than 24 hours old.

Turnaround Times

• Clinical emergency: 30 mins
• Other urgent sample: 60 mins
• Routine: within 2 hours

Reference Ranges

If references ranges are required for paediatric patients please contact the laboratory for these.