Blood Test: Hematology Values in Human Physiology and Medicine

A reference range is a set of values used by a health professional to interpret a set of medical test results. The range is usually defined as the set of values 95% of the normal population falls within.

The reference range will vary, depending on the age, sex and race of a population, and even the instruments the laboratory uses to perform the tests. Furthermore, by definition, 5% of the normal population will fall outside the reference range.

Category Test Low High Unit Comments
Red blood cells Haemoglobin (Hb) (male) 140 180 g/L Higher in neonates, lower in children.
Haemoglobin (Hb) (female) 115 160 g/L Sex difference negligible until adulthood.
Haematocrit (Hct) (male) 0.38 0.52
Haematocrit (Hct) (female) 0.35 0.47
Mean cell volume (MCV) 80 98 fL Cells are larger in neonates, though smaller in other children.
Mean cell haemoglobin (MCH) 26 34 pg
Red cell count (male) 4.5 6.5 x1012/L
Red cell count (female) 3.8 5.8 x1012/L
Reticulocytes 10 100 x109/L
erythrocyte sedimentation rate (ESR) n/a 20 mm/hr Females tend to have a higher ESR. ESR increases with age.
White blood cells The Total white blood cells 4 11 x109/L Higher in neonates and infants.
Neutrophil granulocytes 2 7.5 x109/L 45-74%. Also known as granulocytes (grans), polys, PMNs, or segs.
Lymphocytes 1.3 4 x109/L 16-45%
Monocytes 0.2 0.8 x109/L 4.0-10%
Eosinophil granulocytes 0.04 0.4 x109/L 0.0-7.0%
Basophil granulocytes 0.01 0.1 x109/L 0.0-2.0%
Coagulation Platelets 150 400 x109/L Platelets are part of the formation of blood clots
Prothrombin time (PT)[11] 11 13.5 s PT reference varies between laboratory kits – INR is standardised
INR 0.9 1.2 The INR is a corrected ratio of a patients PT to normal
Activated partial thromboplastin time (APTT) 29 41 s
Thrombin clotting time (TCT) 11 18 s
Fibrinogen 1.8 4 g/L
Bleeding time 2 9 minutes