Unsaturated B12 binding capacity (S) pg/mL pmol/L 0.738 1.355 Vitamin C (ascorbic acid) mg/dL µmol/L 56.78 0.176 Vitamin A µg/dL µmol/L 0.0349 28.65 Vitamin D (calcitriol; 1,25-dihydroxy) pg/mL pmol/L 2.4 0.417

 

µg/dL µg/L 10 0.1

Ammonia µg/dL µmol/L 0.714 1.4

 (P) µg/dL µmol/L 0.5872 1.703

Anion gap mEq/L mmol/L 1 1

Base excess mEq/L mmol/L 1 1

Bicarbonate mEq/L mmol/L 1 1

Bilirubin mg/dL µmol/L 17.1 0.0584

Calcitonin pg/mL ng/L 1 1

Catecholamines (U) µg/24 h nmol/d 5.91 0.169

Norepinephrine µg/mg creatinine µmol/mol

creatinine

669 0.00149

pg/mL pmol/L 5.91 0.169

ng/mL nmol/L 5.91 0.169

Epinephrine µg/24 h nmol/d 5.46 0.183

µg/mg creatinine µmol/mol

creatinine

617 0.00162

pg/mL pmol/L 5.46 0.183

ng/mL nmol/L 5.46 0.183

Normetanephrine ng/mL nmo]/L 5.46 0.183

Dopamine µg 24 h nmol/d 6.53 0.153

µg/mg creatinine µmol/mol

creatinine

783 0.00136

pg/mL pmol/L 6.53 0.153

ng/mL nmol/L 6.53 0.153

Human chorionic gonadotropin (hCG), mU/mL IU/L 1 1

beta, subunit U/24 h IU/d 1 1

Calcium

 (S)

mg/dL mmol/L 0.25 4.0

mEq/L mmol/L 0.5 2.0

Contd...

Contd...

SI Units 45

Contd...

Conversion factors

Analyte Conventional units SI units Conventional to SI units SI to conventional units

 (U) mg/24 h mmol/d 0.025 40

Carbon dioxide total (content; CO2 + mEq/L mmol/L 1 1

bicarbonate)

CO2 partial pressure, tension (PCO2) mm Hg kPa 0.133 7.52

Standard bicarbonate (hydrogen

carbonate

mEq/L mmol/L 1 1 (carbonate)

Chloride mEq/L or mg/dL mmol/L 1 1

CEA ng/mL µg/L 1 1

µg/mL mg/L 1 1

Ceruloplasmin mg/dL mg/L 10 0.1

Cholesterol mg/dL mmol/L 0.0259 38.61

HDL-choIesterol mg/dL mmol/L 0.0259 38.61

LDL-cholesterol mg/dL mmol/L 0.0259 38.61

Copper

 (S) µg/dL µmol/L 0.157 6.37

 (U) µg/24 h µmol/d 0.0157 63.69

Coproporphyrins (I and III) µg/dL nmol/L 15 0.067

 (U) µg/24 h nmol/d 1.5 0.67

 (F) µg/g nmol/g 1.5 0.67

Porphobilinogen (PBG)

 (U) mg/24 h µmol/d 4.42 0.226

Cortisol

 (S) µg/dL µmol/L 0.028 35.7

ng/mL nmol/L 2.76 0.362

17-OHKS (cortisol) mg/24 h µmol/d 2.759 0.3625

 (U) µg/24 hr nmol/d 2.759 0.3625

Creatine mg/dL µmol/L 76.3 0.0131

 (S)

Creatinine

 (S, AF) mg/dL µmol/L 88.4 0.0113

 (U) g/24 h mmol/d 8.84 0.1131

 (U) mg/24 h mmol/d 0.00884 113.1

 (U) mg/kg/24 h µmol/kg/d 8.84 0.113

 (C) mL/min/1.73 m2 mL/sec/m2 0.00963 104

cAMP (cyclic adenosine monophosphate)

 (S) µg/L nmol/L 3.04 0.329

 (B) ng/mL nmol/L 3.04 0.329

 (U) mg/24 h µmol/d 3.04 0.329

Contd...

46 Concise Book of Medical Laboratory Technology: Methods and Interpretations Conversion factors

Analyte Conventional units SI units Conventional to SI units SI to conventional units

 (U) mg/g creatinine µmol/mol 344 0.00291

creatinine

Dehydroepiandrosterone sulfate

(DHEA-S)

 (S) µg/mL µmol/L 2.6 0.38

 (AF) ng/mL nmol/L 2.6 0.38

17-Ketosteroids (as DHEA)

 (U) mg/24 h µmol/d 3.467 0.2904

17-Ketogenic steroids (as DHEA)

 (U) mg/24 h µmol/d 3.467 0.2904

17-Hydroxycorticosteroids (17-OHCS)

 (U) mg/d of creatinine mg/mol 113.1 0.00884

of creatinine

11-Deoxy corticosterone (DOC)

 (S) pg/mL pmol/L 3.03 0.33

Glucose mg/dL mmol/L 0.0555 18.02

Ferritin ng/mL µg/L 1 1

Gastrin pg/mL ng/L 1 1

Growth hormone ng/mL µg/L 1 1

Homovanillic acid (HVA)

 (U) mg/24 h µmol/d 5.49 0.182

µg/24 h µmol/d 0.00549 182

µg/mg of creatinine mmol/mol of 0.621 1.61

creatinine

5-Hydroxyindoleacetic acid (5-HIAA)

 (U) mg/24 h µmol/d 5.2 0.19

Hormone receptors (T)

Progesterone receptor assay (PRA) fmol/mg of protein nmol/kg of 1 1

protein

Estrogen receptor assay (ERA) fmol/mg of protein nmol/kg of 1 1

protein

Iron µg/dL µmol/L 0.179 5.587

Iron-binding capacity µg/dL µmol/L 0.179 5.587

Iron saturation % fraction 0.01 100

saturation

Lactate mg/dL mmol/L 0.111 9.01

Lead

 (S) µg/dL µmol/L 0.0483 20.72

Contd...

Contd...

SI Units 47

Contd...

Contd...

Conversion factors

Analyte Conventional units SI units Conventional to SI units SI to Conventional units

 (S) mg/dL µmol/L 48.26

 (U) µg/24 h µmol/d 0.00483

Lipids (total) mg/dL g/L 0.01 100

Magnesium mEq/L mmol/L 0.5 2

mg/dL mmol/L 0.411 2.433

Osmolality mOsml/kg same

O2 partial pressure (PaO2) mm Hg kPa 0.133 7.5

Parathyroid hormone pg/mL ng/L 1 1

Phosphate (inorganic phosphorus)

 (S) mg/dL mmol/L 0.323 3.10

 (U) g/24 h mmol/d 32.3 0.031

 pH nEq/L nmol/L 1 1

Porphobilinogen µg/d µmol/d 4.42 0.226

Potassium

 (S) mEq/L mmol/L 1 1

 (U) mEq/24 h mmol/L 1 1

 (U) mg/24 h nmol/d 0.02558 39.1

Protein, total

 (S) g/dL gm/L 10 0.1

 (U) mg/24 h gm/d 0.001 1000

 CSF mg/dL mg/L 10 0.1

Renin [plasma-renin activity (PRA)] ng/mL/h µg/L/hr 1 1

Sodium

 (S) mEq/L mmol/L 1 1

 (U) mEq/24 h mmol/L 1 1

 (U) mmol/d 0.0435 22.99

Serotonin

 (S) ng/mL µmol/L 0.00568 176

Testosterone (total)

 (S) ng/dL nmol/L 0.0347 28.8

Thyroid-binding globulin (TBG) mg/dL mg/L 10 0.1

µg/dL µg/L 10 0.1

Thyroglobulin ng/mL µg/L 1 1

TSH (thyroid-stimulating hormone) µU/mL mIU/L 1 1

Thyrotropin-releasing hormone (TRH) pg/mLL ng/L 1 1

Triiodothyronine, total (T3) ng/dL nmol/L 0.0154 65.1

Reverse T3 (rT3) ng/dL nmol/L 0.0154 65.1

48 Concise Book of Medical Laboratory Technology: Methods and Interpretations Contd...

Conversion factors

Analyte Conventional units SI units Conventional to SI units SI to Conventional

units

Thyroxine, total (T4) µg/dL nmol/L 12.9 0.0775

Transferrin (TIBC) mg/dL g/L 0.01 100

Triglycerides mg/dL mmol/L 0.0113 88.5

Urea nitrogen

 (S) mg/dL mmol/L 0.357 2.8

 (U) g/24 h mol/d 0.0357 28

Uric acid

 (S) mg/dL mmol/L 0.05948 16.9

 (U) mg/24 h mmol/d 0.0059 169

Vanillylmandelic acid (VMA)

 (U) mg/24 h µmol/d 5.05 0.198

µg/mg of creatinine mmol/mol of 0.571 1.75

creatinine

Viscosity (S) centipoise same

Vitamin B12 (cyanocobalamin) pg/mL pmol/L 0.738 1.355

Unsaturated B12 binding capacity

 (S) pg/mL pmol/L 0.738 1.355

Vitamin C (ascorbic acid) mg/dL µmol/L 56.78 0.176

Vitamin A µg/dL µmol/L 0.0349 28.65

Vitamin D (calcitriol; 1,25-dihydroxy) pg/mL pmol/L 2.4 0.417

Xylose (U) mg/dL mmol/L 0.0666 15.01

g/5 h mmol/5 h 6.66 0.15

(µ = microns; µmol = micromoles; mmol = millimoles; nmol = nanomoles; fmol = fentamoles; mg = milligrams; g = grams;

pg = picograms; ng = nanograms; L = liter; mL = milliliter; mEq = milliequivalent; mL/sec = milliliter/second; mL/min = milliliter/minute; U = units; mU = milliunits; IU = international units; d = day; 24 h = 24 hours; S = serum; U = urine; B = blood;

C = clearance; F = feces; AF = amniotic fluid; SF = synovial fluid; T = tissue. All references are to serum unless otherwise

indicated).