Reference ranges for common blood tests
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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.
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.
| Contents |
Clinical biochemistry
Electrolytes and Metabolytes
| Test | Range | Comments |
|---|---|---|
| Sodium (Na) | 130 - 145 mmol/L | |
| Potassium (K) | 3.5 - 5.0 mmol/L | |
| Urea | 2.6 - 6.8 mmol/L | |
| Creatinine | 50 - 110 μmol/L | |
| Glucose (fasting) | 4.2 - 6.1 mmol/L |
Liver function tests
| Total Protein | 60 - 80 g/L | |
| Albumin | 30 - 50 g/L | |
| Total Bilirubin | 2 - 14 μmol/L | |
| Direct Bilirubin | 0 - 4 μmol/L | |
| Alanine transaminase (ALT) | 8 - 40 U/L | Also called serum glutamic pyruvic transaminase (SGPT) |
| Alkaline phosphatase (ALP) | 40 - 130 U/L | Higher in children and pregnant women. |
| Gamma glutamyl transferase | < 50 U/L |
Other enzymes and proteins
| Creatine kinase (CK) | 22 - 198 U/L |
| Aspartate transaminase (AST) | 8 - 35 U/L |
| Lactate dehydrogenase (LDH) | 85 - 285 U/L |
| Amylase | 25 - 125 U/L |
| C-reactive protein (CRP) | <8 mg/L |
| D-dimer | <500 ng/ml |
Other ions and trace metals
| Ionised calcium (Ca) | 1.15 - 1.29 mmol/L | Some 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 |
Lipids
| Triglycerides | 0.4 - 2.0 mmol/L | |
| Total cholesterol | 3.0 - 5.5 mmol/L | |
| HDL cholesterol (male) | 0.7 - 1.9 mmol/L | |
| (female) | 0.9 - 2.4 mmol/L | |
| LDL cholesterol | 2.4 - 4.0 mmol/l | Not 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/L | After age 40, normal levels increase every decade. |
Hormones
| Thyroid stimulating hormone (TSH) | 0.5 - 4.7 mIU/L | Also 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/L | Cortisol 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 |
Haematology
Red blood cells
| Haemoglobin (Hb) (male) | 130 - 180 g/L | Higher in neonates, lower in children. |
| (female) | 115 - 160 g/L | Sex difference negligible until adulthood. |
| Haematocrit (Hct) (male) | 0.38 - 0.52 | |
| (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 | |
| (female) | 3.8 - 5.8 x1012/L | |
| Reticulocytes | 10 - 100 x109/L | |
| Erythrocyte sedimentation rate (ESR) | <20 mm/hr | Females tend to have a higher ESR. ESR increases with age. |
White blood cells
| The Total white blood cells | 4.0 - 11.0 x109/L | Higher in neonates and infants. |
| Neutrophil granulocytes | 2.0 - 7.5 x109/L | |
| Lymphocytes | 1.0 - 4.0 x109/L | |
| Monocytes | 0.0 - 0.8 x109/L | |
| Eosinophil granulocytes | 0.0 - 0.5 x109/L | |
| Basophil granulocytes | 0.0 - 0.2 x109/L |
Coagulation
| Prothrombin time (PT) | 7 - 10 s | |
| INR | 0.8 - 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 - 4.0 g/L | |
| Bleeding time | 2 - 8 minutes |
Immunology
| Antinuclear antibodies (ANA) | ||
| Extractable nuclear antigen (ENA) |