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Reference Ranges

U.S. traditional units are followed in parentheses by equivalent values expressed in S.I. units.

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Absolute neutrophil count—greater than 1500/μL (1.50 × 109/L)
Activated partial thromboplastin time—25-35 s
D-dimer—less than 0.5 μg/mL (0.5 mg/L)
Erythrocyte count—4.2-5.9 × 106/μL (4.2-5.9 × 1012/L)
Erythrocyte sedimentation rate
     Male—0-15 mm/h
     Female—0-20 mm/h
Erythropoietin—5-36 mU/mL (5-36 U/L)
Haptoglobin, serum—50-150 mg/dL (500-1500 mg/L)
Hemoglobin, blood
     Male—14-17 g/dL (140-170 g/L)
     Female—12-16 g/dL (120-160 g/L)
Leukocyte count—4000-10,000/μL (4.0-10 × 109/L)
Mean corpuscular hemoglobin—28-32 pg
Mean corpuscular hemoglobin concentration—32-36 g/dL (320-360 g/L)
Mean corpuscular volume—80-100 fL
Platelet count—150,000-450,000/μL (150-450 × 109/L)
Prothrombin time—11-13 s
Reticulocyte count—0.5%-1.5% of erythrocytes; absolute: 23,000-90,000/μL (23-90 × 109/L)

Blood, Plasma, and Serum Chemistry Studies

Albumin, serum—3.5-5.5 g/dL (35-55 g/L)
Alkaline phosphatase, serum—36-92 U/L
α-Fetoprotein, serum—0.6-6.6 ng/mL (0.6-6.6 μg/L)
Aminotransferase, alanine (ALT)—0-35 U/L
Aminotransferase, aspartate (AST)—0-35 U/L
Ammonia, plasma—40-80 μg/dL (23-47 μmol/L)
Amylase, serum—0-130 U/L
Bilirubin, serum
     Total—0.3-1.2 mg/dL (5.1-20.5 μmol/L)
     Direct—0-0.3 mg/dL (0-5.1 μmol/L)
Blood gases, arterial (ambient air)
     Pco2—35-45 mm Hg (4.7-6.0 kPa)
     Po2—80-100 mm Hg (10.6-13.3 kPa)
     Oxygen saturation—95% or greater
Blood urea nitrogen—8-20 mg/dL (2.9-7.1 mmol/L)
B-type natriuretic peptide level
     Heart failure unlikely—less than 100 pg/mL (100 ng/L)
     Heart failure likely—greater than 400 pg/mL (400 ng/L)
Calcium, serum—9-10.5 mg/dL (2.2-2.6 mmol/L)
Carbon dioxide, serum—See Bicarbonate
Chloride, serum—98-106 mEq/L (98-106 mmol/L)
Complement, serum
     C3—55-120 mg/dL (550-1200 mg/L)
     C4—10-40 mg/dL (100-400 mg/L)
C-reactive protein, blood—0-0.8 mg/dL (0-8.0 mg/L)
Cardiovascular risk prediction
     Low risk—less than 1.0 mg/L
     Average risk—1.0-3.0 mg/L
     High risk—greater than 3.0 mg/L
Creatine kinase, serum—30-170 U/L
Creatinine, serum—0.7-1.3 mg/dL (61.9-115 μmol/L)
Electrolytes, serum
     Sodium—136-145 mEq/L (136-145 mmol/L)
     Potassium—3.5-5.0 mEq/L (3.5-5.0 mmol/L)
     Chloride—98-106 mEq/L (98-106 mmol/L)
     Bicarbonate—23-28 mEq/L (23-28 mmol/L)
Fibrinogen, plasma—150-350 mg/dL (1.5-3.5 g/L)
Folate, serum—4.0-20 ng/mL (9.1-45.3 nmol/L)
Glucose, plasma—fasting, 70-100 mg/dL (3.9-5.6 mmol/L)
γ-Glutamyltransferase, serum—0-30 U/L
     Globulins, total—2.5-3.5 g/dL (25-35 g/L)
     IgG—640-1430 mg/dL (6.4-14.3 g/L)
     IgA—70-300 mg/dL (0.7-3.0 g/L)
     IgM—20-140 mg/dL (0.2-1.4 g/L)
     IgD—less than 8 mg/dL (80 mg/L)
     IgE—0-90 U/mL (0-90 kU/L)
Iron studies
     Ferritin, serum—15-200 ng/mL (15-200 μg/L)
     Iron, serum—60-160 μg/dL (11-29 μmol/L)
     Iron-binding capacity, total (TIBC), serum—250-460 μg/dL (45-82 μmol/L)
     Transferrin saturation—20%-50% (serum iron ÷ TIBC x 100)
Lactate dehydrogenase, serum—60-100 U/L
Lactate, plasma—0.5-2.2 mEq/L (0.5-2.2 mmol/L)
Lipase, serum—13-60 U/L
Magnesium, serum—1.5-2.4 mg/dL (0.62-0.99 mmol/L)
Osmolality, serum—275-295 mOsm/kg H2O
Phosphatase, alkaline, serum—36-92 U/L
Phosphorus, serum—3.0-4.5 mg/dL (0.97-1.45 mmol/L)
Prostate-specific antigen, serum—less than 4 ng/mL (4 μg/L)
Protein, serum
     Total—6.0-7.8 g/dL (60-78 g/L)
     Albumin—3.5-5.5 g/dL (35-55 g/L)
     Globulins, total—2.5-3.5 g/dL (25-35 g/L)
Rheumatoid factor—less than 40 U/mL (40 kU/L)
Triglycerides—less than 150 mg/dL (1.69 mmol/L), desirable
Troponins, serum
     Troponin I—0-0.1 ng/mL (0-0.1 μg/L)
     Troponin T—0-0.1 ng/mL (0-0.1 μg/L)
Urate, serum
     Male—3.7-8.6 mg/dL (0.22-0.50 mmol/L)
     Female—2.4-5.8 mg/dL (0.14-0.34 mmol/L)
Vitamin B12, serum—200-800 pg/mL (148-590 pmol/L)


Adrenocorticotropic hormone (ACTH), serum—9-52 pg/mL (2-11 pmol/L)
Aldosterone, serum
     Supine—2-5 ng/dL (55-138 pmol/L)
     Standing—7-20 ng/dL (194-554 pmol/L)
Aldosterone, urine—5-19 μg/24 h (13.9-52.6 nmol/24 h)
Catecholamines, fractionated, urine
     Epinephrine—2-24 μg/24 h (10.92-131.04 nmol/24 h)
     Norepinephrine—15-100 μg/24 h (88.65-591 nmol/24 h)
     Dopamine—52-480 μg/24 h (339.56-3134.4 nmol/24 h)
Cortisol, free, urine—less than 50 μg/24 h (138 nmol/24 h)
Cortisol, serum, morning—5-25 μg/dL (138-690 nmol/L)
Dehydroepiandrosterone sulfate (DHEAS), plasma
     Male—1.3-5.5 μg/mL (3.5-14.9 μmol/L)
     Female—0.6-3.3 μg/mL (1.6-8.9 μmol/L)
Epinephrine, plasma (supine)—less than 75 ng/L (410 pmol/L)
Estradiol, serum
     Male—10-30 pg/mL (37-110 pmol/L)
     Female—day 1-10, 14-27 pg/mL (50-100 pmol/L); day 11-20, 14-54 pg/mL (50-200 pmol/L); day 21-30, 19-41 pg/mL (70-150 pmol/L)
Follicle-stimulating hormone, serum
     Male (adult)—5-15 mU/mL (5-15 U/L)
     Female—follicular or luteal phase, 5-20 mU/mL (5-20 U/L); midcycle peak, 30-50 mU/mL (30-50 U/L); postmenopausal, greater than 35 mU/mL (35 U/L)
Growth hormone, plasma—after oral glucose, less than 2 ng/mL (2 μg/L); response to provocative stimuli, greater than 7 ng/mL (7 μg/L)
Hemoglobin A1c, blood—less than 5.7%
Luteinizing hormone, serum
     Male—3-15 mU/mL (3-15 U/L)
     Female—follicular or luteal phase, 5-22 mU/mL (5-22 U/L); midcycle peak, 30-250 mU/mL (30-250 U/L); postmenopausal, greater than 30 mU/mL (30 U/L)
Metanephrines, fractionated, urine
     Metanephrine, unconjugated—90-315 μg/24 h (456-1597 nmol/24 h)
     Normetanephrine—122-676 μg/24 h (666-3691 nmol/24 h)
     Metanephrines, total—224-832 μg/24 h (1136-4218 nmol/24 h)
Metanephrines, fractionated, plasma
     Metanephrine, free—less than or equal to 57 pg/mL (0.2964 nmol/L)
     Normetanephrine, free—less than or equal to 148 pg/mL (0.8288 nmol/L)
     Metanephrines, total—less than or equal to 205 pg/mL (1.066 nmol/L)
Parathyroid hormone, serum—10-65 pg/mL (10-65 ng/L)
Progesterone, blood
      Male (adult)—0.27-0.9 ng/mL (0.9-2.9 nmol/L)
      Female—follicular phase, 0.33-1.20 ng/mL (1.0-3.8 nmol/L); luteal phase, 0.72-17.8 ng/mL (2.3-56.6 nmol/L); postmenopausal, less than 0.2-1 ng/mL (0.6-3.18 nmol/L); oral contraceptives, 0.34-0.92 ng/mL (1.1-2.9 nmol/L)
Prolactin, serum
     Male—less than 15 ng/mL (15 μg/L)
     Female—less than 20 ng/mL (20 μg/L)
Testosterone, total, serum
     Male (adult)—300-1200 ng/dL (10-42 nmol/L)
     Female—20-75 ng/dL (0.7-2.6 nmol/L)
Thyroid iodine (131I) uptake—10%-30% of administered dose at 24 h
Thyroid-stimulating hormone (TSH)—0.5-5.0 μU/mL (0.5-5.0 mU/L)
Thyroxine (T4)
     Total, serum—5-12 μg/dL (64-155 nmol/L)
     Free—0.9-2.4 ng/dL (12-31 pmol/L)
     Free T4 index—4-11
Triiodothyronine (T3)
     Total, serum—70-195 ng/dL (1.1-3.0 nmol/L)
     Free—3.6-5.6 ng/L (5.6-8.6 pmol/L)
Vitamin D
     1,25-dihydroxy, serum—25-65 pg/mL (60-156 pmol/L)
     25-hydroxy, serum—31-80 ng/mL (77-200 nmol/L)


Albumin-creatinine ratio—less than 30 mg/g
Calcium—100-300 mg/24 h (2.5-7.5 mmol/24 h) on unrestricted diet
Creatinine—15-25 mg/kg per 24 h (133-221 mmol/kg/24 h)
Glomerular filtration rate (GFR)
     Categories of Chronic Kidney Disease (from KDIGO)
          Stage G1—greater than or equal to 90 mL/min/1.73 m2
          Stage G2—60-89 mL/min/1.73 m2
          Stage G3a—45-59 mL/min/1.73 m2
          Stage G3b—30-44 mL/min/1.73 m2
          Stage G4—15-29 mL/min/1.73 m2
          Stage G5—less than 15 mL/min/1.73 m2
          Albuminuria categories
               A1 (Normal)—less than 30 mg/g
               A2 (Moderately increased)—30-300 mg/g
               A3 (Severely increased)—greater than 300 mg/g
Protein-creatinine ratio—less than or equal to 150 mg/g
Uric acid—250-750 mg/24 h (1.48-4.43 mmol/24 h) (varies with diet)


Forced expiratory volume in 1 second (FEV1)—greater than 80% of predicted
Forced vital capacity (FVC)—greater than 80% of predicted
FEV1/FVC—greater than 0.70

Cerebrospinal Fluid

Cell count—0-5/μL (0-5 × 106/L)
Glucose—40-80 mg/dL (2.2-4.4 mmol/L); less than 40% of simultaneous plasma concentration is abnormal
Pressure (opening)—70-200 mm H2O
Protein—15-60 mg/dL (150-600 mg/L)

Hemodynamic Measurements

Cardiac index—2.5-4.2 L/min/m2
Left ventricular ejection fraction—greater than 55%
     Pulmonary artery
          Systolic—20-25 mm Hg
          Diastolic—5-10 mm Hg
          Mean—9-16 mm Hg
     Pulmonary capillary wedge—6-12 mm Hg
     Right atrium—mean 0-5 mm Hg
     Right ventricle
          Systolic—20-25 mm Hg
          Diastolic—0-5 mm Hg