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Reference ranges for common blood tests

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

It must be remembered that the reference range will vary, depending on the age, sex and race of a population, and even the machines the laboratory[?] uses to do the tests. Also remember that by definition 5% of the normal population will fall outside the reference range.

These are approximate adult values that are intended as a guide to students and those interested, they are not a substitute for medical advice.

Table of contents

Clinical biochemistry[?]

Electrolytes and Metabolytes

Sodium (Na)130 - 145 mmol/L
Potassium (K)3.5 - 5.0 mmol/L
Urea2.6 - 6.8 mmol/L
Creatinine50 - 110 μmol/L
Glucose (fasting)4.2 - 6.1 mmol/L

Liver function tests

Total Protein60 - 80 g/L
Albumin30 - 50 g/L
Total Bilirubin2 - 14 μmol/L
Direct Bilirubin0 - 4 μmol/L
Alanine transaminase (ALT)8 - 40 U/LAlso called serum glutamic pyruvic transaminase (SGPT)
Alkaline phosphatase[?] (ALP)40 - 130 U/LHigher in children and pregnant women.
Gamma glutamyl transferase[?]< 50 U/L

Other enzymes and proteins

Creatine kinase[?] (CK)
Aspartate transaminase[?] (AST)8 - 35 U/L
Lactate dehydrogenase[?] (LDH)85 - 285 U/L
Amylase25 - 125 U/L
C-reactive protein[?] (CRP)<8 mg/L

Other ions and trace metals[?]

Ionised calcium (Ca)1.15 - 1.29 mmol/LSome calcium is bound to albumin, thus not measured by certain techniques.
Total calcium (Ca)2.05 - 2.55 mmol/L
Copper (Cu)11 - 26 μmol/L
Zinc (Zn)10 - 17 μmol/L


Triglycerides0.4 - 2.0 mmol/L
Total cholesterol3.0 - 5.5 mmol/L
HDL cholesterol (male)0.7 - 1.9 mmol/L
(female)0.9 - 2.4 mmol/L
LDL cholesterol2.4 - 4.0 mmol/lNot valid when triglycerides >5.0 mmol/L.

Tumour markers[?]

Alpha-fetoprotein (AFP)1-15 kIU/L
CA-125[?]<65 kU/L
Prostate specific antigen[?] (total PSA)<2.0 μg/LAfter age 40, normal levels increase every decade.


Thyroid stimulating hormone[?] (TSH)0.5 - 4.7 mIU/LAlso called: Thyrotropin
Free thyroxine (FT4)9.0 - 24 pmol/L
Free triiodothyronine[?] (FT3)2.5 - 5.3 pmol/L
Adrenocorticotropic hormone (ACTH)1.3 - 15 pmol/L
Cortisol[?] (0830 h)250 - 850 nmol/LCortisol levels are higher in the morning than at night.
Cortisol (1630 h)110 - 390 nmol/L
Prolactin (male)<450 mIU/L
(female)<580 mIU/L
Testosterone (male)8 - 38 nmol/L
(male prepuberty)0.1 - 0.5 nmol/L
(female)0.3 - 2.5 nmol/L


Red blood cells

Haemoglobin (Hb) (male)130 - 180 g/LHigher in neonates[?], lower in children.
(female)115 - 160 g/LSex difference negligible until adulthood.
Haematocrit[?] (Hct) (male)0.38 - 0.52
(female)0.35 - 0.47
Mean cell volume (MCV)80 - 98 fL
Mean cell haemoglobin (MCH)26 - 34 pg
Red cell count (male)4.5 - 6.5 x1012/L
(female)3.8 - 5.8 x1012/L
Reticulocytes10 - 100 x109/L
sedimentation rate (ESR)

White blood cells

Total white blood cells4.0 - 11.0 x109/LHigher in neonates[?] and infants.
Neutrophils2.0 - 7.5 x109/L
Lymphocytes[?]1.0 - 4.0 x109/L
Monocytes[?]0.0 - 0.8 x109/L
Eosinophils0.0 - 0.5 x109/L
Basophils[?]0.0 - 0.2 x109/L


Prothrombin time (PT)7 - 10 s
INR0.8 - 1.2The 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
Fibrinogen1.8 - 4.0 g/L
Bleeding time2 - 8 minutes


Antinuclear antibodies[?] (ANA)
Extractable nuclear antigen[?] (ENA)


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