Haemoglobin

Haemoglobin (Hb) is an iron-containing pigment, which binds to and transports oxygen. Haemoglobin levels are determined by measuring the colour intensity of a blood sample in which the red cells have been lysed (broken open).Red cell count (RBC)

The red cell count (RBC) is an estimation of the number of red cells present in 1ml of whole blood. The exact method used to count the red cells varies between different designs of automated cell counter. The normal red cell count varies according to age and sex. If performed on an electronic counter this is a very accurate estimation. The principle source of error is the quality of the blood sample submitted.

Mean cell volume (MCV)

Mean cell volume (MCV) is a measurement of the average size of the red cells. The normal range of the MCV is between 80 and 99fl.

Packed cell volume (PCV)

The packed cell volume (PCV) is often referred to as the haematocrit. It measures what percentage of a given volume of blood is made up of red blood cells. On automated counters the PCV is usually a calculated value derived from the RBC and the MCV. The PCV is affected by many conditions other than anaemia. Certainly the PCV alone can never be used to diagnose anaemia. The PCV may be reported as a percentage or as litres/litre.