SI Units for Clinical Data

The following table provides factors for converting conventional units to SI units for selected clinical data. Source: JAMA Author Instructions.

Conversion:

  • to convert from the conventional unit to the SI unit, multiply by the conversion factor;
  • to convert from the SI unit to the conventional unit, divide by the conversion factor.
  •  
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Component
 
Conventional
Unit
Conversion
Factor
SI Unit
 
Acetaminophen µg/mL 6.62 µmol/L
Acetoacetic acid mg/dL 0.098 mmol/L
Acetone mg/dL 0.172 mmol/L
Acid phosphatase units/L 1.0 U/L
Alanine mg/dL 112.2 µmol/L
Alanine aminotransferase (ALT) units/L 1.0 U/L
Albumin g/dL 10 g/L
Alcohol dehydrogenase units/L 1.0 U/L
Aldolase units/L 1.0 U/L
Aldosterone ng/dL 0.0277 nmol/L
Alkaline phosphatase units/L 1.0 U/L
Aluminum ng/mL 0.0371 µmol/L
Aminobutyric acid mg/dL 97 µmol/L
Amitriptyline ng/mL 3.61 nmol/L
Ammonia (as NH3) µg/dL 0.587 µmol/L
Amylase units/L 1.0 U/L
Androstenedione ng/dL 0.0349 nmol/L
Angiotensin I pg/mL 0.772 pmol/L
Angiotensin II pg/mL 0.957 pmol/L
Anion gap mEq/L 1.0 mmol/L
Antidiuretic hormone pg/mL 0.923 pmol/L
Antithrombin III mg/dL 10 mg/L
alpha1-Antitrypsin mg/dL 0.184 µmol/L
Apolipoprotein A mg/dL 0.01 g/L
Apolipoprotein B mg/dL 0.01 g/L
Arginine mg/dL 57.4 µmol/L
Asparagine mg/dL 75.7 µmol/L
Aspartate aminotransferase (AST) units/L 1.0 U/L
Bicarbonate mEq/L 1.0 mmol/L
Bilirubin mg/dL 17.1 µmol/L
Blood gases (arterial)      
     Paco2 mm Hg 1.0 mm Hg
     pH pH units 1.0 pH units
     Pao2 mm Hg 1.0 mm Hg
Bromide mg/dL 0.125 mmol/L
C-peptide ng/mL 0.333 nmol/L
C1 esterase inhibitor mg/dL 10 mg/L
C3 complement mg/dL 0.01 g/L
C4 complement mg/dL 0.01 g/L
Calcitonin pg/mL 1.0 ng/L
Calcium mg/dL 0.25 mmol/L
  mEq/L 0.50 mmol/L
Carbon dioxide mEq/L 1.0 mmoI/L
Carboxyhemoglobin % of
hemoglobin saturation
0.01 Proportion of
hemoglobin saturation
Carotene µg/dL 0.0186 µmol/L
Ceruloplasmin mg/dL 10 mg/L
Chloride mEq/L 1.0 mmol/L
Cholesterol mg/dL 0.0259 mmol/L
Citrate mg/dL 52.05 µmol/L
Copper µg/dL 0.157 µmoI/L
Coproporphyrins (urine) µg/24 hr 1.527 nmol/d
Corticotropin (ACTH) pg/mL 0.22 pmol/L
Cortisol µg/dL 27.59 nmol/L
Cotinine ng/mL 5.68 nmol/L
Creatine mg/dL 76.26 µmol/L
Creatine kinase (CK) units/L 1.0 U/L
Creatinine mg/dL 88.4 µmol/L
Creatinine clearance mL/min 0.0167 mL/s
Cyanide mg/L 23.24 µmol/L
Dehydroepiandrosterone (DHEA) ng/mL 3.47 nmol/L
Desipramine ng/mL 3.75 nmol/L
Diazepam µg/mL 3.512 µmol/L
Digoxin ng/mL 1.281 nmol/L
Epinephrine pg/mL 5.46 pmol/L
Erythrocyte sedimentation rate mm/h 1.0 mm/h
Estradiol pg/mL 3.671 pmol/L
Estriol ng/mL 3.467 nmol/L
Estrone ng/dL 37 pmoI/L
Ethanol (ethyl alcohol) mg/dL 0.217 mmol/L
Ethylene glycol mg/L 16.11 µmol/L
Ferritin ng/mL 2.247 pmol/L
alpha -Fetoprotein ng/mL 1.0 µg/L
Fibrinogen mg/dL 0.0294 µmol/L
Fluoride µg/mL 52.6 µmol/L
Folate ng/mL 2.266 nmol/L
Follicle-stimulating hormone mIU/mL 1.0 IU/L
Fructose mg/dL 55.5 µmol/L
Galactose mg/dL 55.506 µmol/L
Glucagon pg/mL 1.0 ng/L
Glucose mg/dL 0.0555 mmol/L
Glutamine mg/dL 68.42 µmol/L
gamma -Glutamyltransferase (GGT) units/L 1.0 U/L
Glycated hemoglobin (glycosylated
hemoglobin A1, A1C)
% of total
hemoglobin
0.01 Proportion of total
hemoglobin
Glycerol (free) mg/dL 108.59 µmol/L
Glycine mg/dL 133.3 µmol/L
Haptoglobin mg/dL 0.10 µmol/L
Hematocrit % 0.01 Proportion
of 1.0
Hemoglobin (whole blood)
Mass concentration
g/dL 10.0
0.6206
g/L
mmol/L
High-density lipoprotein cholesterol (HDL-C) mg/dL 0.0259 mmol/L
Histidine mg/dL 64.45 µmol/L
Homocysteine (total) mg/L 7.397 µmol/L
Human chorionic gonadotropin (HCG) mlU/mL 1.0 IU/L
Hydroxybutyric acid mg/dL 96.05 µmol/L
Hydroxyproline mg/dL 76.3 µmol/L
Immunoglobulin A (IgA) mg/dL 0.01 g/L
Immunoglobulin D (IgD) mg/dL 10 mg/L
Immunoglobulin E (IgE) mg/dL 10 mg/L
Immunoglobulin G (IgG) mg/dL 0.01 g/L
Immunoglobulin M (IgM) mg/dL 0.01 g/L
Insulin µIU/mL 6.945 pmol/L
Iron, total µg/dL 0.179 µmol/L
Iron binding capacity, total µg/dL 0.179 µmol/L
lsoleucine mg/dL 76.24 µmol/L
lsopropanol mg/L 0.0166 mmol/L
Lactate (lactic acid) mg/dL 0.111 mmol/L
Lactate dehydrogenase units/L 1 U/L
Lactate dehydrogenase
isoenzymes (LD1-LD5)
% 0.01 Proportion of 1.0
Lead µg/dL 0.0483 µmol/L
Leucine mg/dL 76.237 µmol/L
Lipase units/L 1.0 U/L
Lipids (total) mg/dL 0.01 g/L
Lipoprotein (a) mg/dL 0.0357 µmol/L
Lithium mEq/L 1.0 mmol/L
Low-density lipoprotein
cholesterol (LDL-C)
mg/dL 0.0259 mmol/L
Luteinizing hormone (LH, leutropin) IU/L 1.0 lU/L
Lysine mg/dL 68.5 µmol/L
Magnesium mg/dL 0.411 mmol/L
  mEq/L 0.50 mmol/L
Manganese ng/mL 18.2 nmol/L
Methanol mg/L 0.0312 mmol/L
Methemoglobin % of total
hemoglobin
0.01 Proportion of total
hemoglobin
Methionine mg/dL 67.02 µmol/L
Myoglobin µg/L 0.0571 nmol/L
Nicotine mg/L 6.164 µmol/L
Nitrogen, nonprotein mg/dL 0.714 mmol/L
Norepinephrine pg/mL 0.00591 nmol/L
Ornithine mg/dL 75.67 µmol/L
Osmolality mOsm/kg 1.0 mmoI/kg
Osteocalcin µg/L 0.171 nmol/L
Oxalate mg/L 11.1 µmol/L
Parathyroid hormone pg/mL 1.0 ng/L
Phenobarbital mg/L 4.31 µmol/L
Phenylalanine mg/dL 60.54 µmol/L
Phenytoin µg/mL 3.96 µmoI/L
Phosphorus mg/dL 0.323 mmol/L
Plasminogen mg/dL 0.113 µmol/L
  % 0.01 Proportion of 1.0
Plasminogen activator inhibitor mIU/mL 1.0 IU/L
Platelets (thrombocytes) x 103/µL 1.0 x 109/L
Potassium mEq/L 1.0 mmoI/L
Pregnanediol (urine) mg/24h 3.12 µmoI/d
Pregnanetriol (urine) mg/24 h 2.97 µmol/d
Progesterone ng/mL 3.18 nmol/L
Prolactin µg/L 43.478 pmol
Proline mg/dL 86.86 µmol/L
Prostate-specific antigen ng/mL 1.0 µg/L
Protein, total g/dL 10.0 g/L
Prothrombin g/L 13.889 µmol/L
Prothrombin time (protime, PT) s 1.0 s
Protoporphyrin, erythrocyte µg/dL 0.01777 µmol/L
Pyruvate mg/dL 113.6 µmoI/L
Quinidine µg/mL 3.08 µmol/L
Red blood cell count x 106/µL 1.0 x 1012/L
Renin pg/mL 0.0237 pmol/L
Reticulocyte count % of RBCs 0.01 Proportion
of 1.0
Salicylate mg/L 0.00724 mmol/L
Serine mg/dL 95.2 µmol/L
Serotonin (5-hydroxytryptamine) ng/mL 0.00568 µmol/L
Sodium mEq/L 1.0 mmol/L
Somatomedin-C (insulinlike growth factor) ng/mL 0.131 nmol/L (coagulation factor II)
Somatostatin pg/mL 0.611 pmol/L
Taurine mg/dL 79.91 µmol/L
Testosterone ng/dL 0.0347 nmol/L
Theophylline µg/mL 5.55 µmol/L
Thiocyanate mg/L 17.2 µmol/L
Threonine mg/dL 83.95 µmol/L
Thyroglobulin ng/mL 1.0 µg/L
Thyrotropin (thyroid-stimulating
hormone, TSH)
mIU/L 1.0 mIU/L
Thyroxine, free (T4) ng/dL 12.87 pmol/L
Thyroxine, total (T4) µg/dL 12.87 nmol/L
Transferrin mg/dL 0.01 g/L
Triglycerides mg/dL 0.0113 mmol/L
Triiodothyronine      
     Free (T3) pg/dL 0.0154 pmol/L
     Resin uptake % 0.01 Proportion of 1.0
     Total (T3) ng/dL 0.0154 nmol/L
Troponin I (cardiac) ng/mL 1.0 µg/L
Troponin T (cardiac) ng/mL 1.0 µg/L
Tryptophan mg/dL 48.97 µmol/L
Tyrosine mg/dL 55.19 µmol/L
Urea nitrogen mg/dL 0.357 mmol/L
Uric acid mg/dL 59.48 µmol/L
Valine mg/dL 85.5 µmol/L
Vasoactive intestinal
polypeptide
pg/mL 1.0 ng/L
Vitamin A (retinol) µg/dL 0.0349 µmoI/L
Vitamin B6 (pyridoxine) ng/mL 4.046 nmol/L
Vitamin B12 (cyanocobalamin) pg/mL 0.738 pmol/L
Vitamin C (ascorbic acid) mg/dL 56.78 µmol/L
Vitamin D      
    1,25-Dihydroxyvitamin D pg/mL 2.6 pmol/L
    25-Hydroxyvitamin D ng/mL 2.496 nmol/L
Vitamin E mg/dL 23.22 µmoI/L
Vitamin K ng/mL 2.22 nmol/L
Warfarin µg/mL 3.247 µmol/L
White blood cell count x 103/µL 1.0 x 109/L
White blood cell differential
count (number fraction)
% 0.01 Proportion of 1.0
Zinc µg/dL 0.153 µmoI/L