Blood Test: Immunology 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
Acute phase protein markers of Inflammation Erythrocyte sedimentation rate (ESR) 0 (Age, +10 if female)/2 mm/hr
C-reactive protein (CRP) 0 6 mg/L
Autoantibodies Antinuclear antibodies (ANA)
Extractable nuclear antigen (ENA)
Rheumatoid factor (RF) 0 20 IU/mL High levels not specific for Rheumatoid Arthritis alone.
Serology Antistreptolysin O titre (ASOT) – preschoolers n/a 100 units/mL
Antistreptolysin O titre (ASOT) – others n/a 200 units/mL