International System of Units (SI Units)
advertisement
International System of Units (SI Units) Système International d’Unités, or SI units, are an extension of the meter, kilogram, second, ampere (MKSA) system proposed in 1950. In 1966, the International Federation of Clinical Chemistry (IFCC) recommended the use of selected, or favored, SI units for the clinical laboratory: whenever possible, use mole and liter units to express concentration, and express whole-unit multiples of three as powers of ten (eg, millimole = 10–3 moles, micromole = 10–6 moles, nanomole = 10–9 moles, picomole = 10–12 moles). This approach was designed to provide clearer quantitative relationships among molecular species and some standardization of databases. This partial application of SI units to laboratory data has been accepted by many scientific journals and is used increasingly in day-to-day clinical medicine. The operative words are “whenever possible.” In many instances the molecular weight or the homogeneity of the measured analyte is not clear, and gravimetric units rather than molar units are preferred. With regard to laboratory reports, we remain in a transition state between conventional (gravimetric) units and SI units. Quest Diagnostics is moving to SI units but continues to use selected conventional units during what has become a prolonged transition period. For your convenience, we have included a guide for interconversion of conventional and SI units, along with definitions of abbreviations used. The following table lists gravimetric and possible international unitage for a variety of laboratory tests. The conversion factor (CF) is used as follows: gravimetric × CF = international unit international ÷ CF = gravimetric unit Definition bone collagen equivalent creatinine day deciliter gram hour international units katal (mol/s) liter milligram minute milliliter milliliter/hour mole millimole milli international units nanogram picogram picomole second units microgram micromole microunits year SI Units Abbreviation BCE creat d dL g h IU kat L mg min mL mL/h mol mmol mIU ng pg pmol s U μg μmol μU y 339 86270_Endocrinology_P4.indd 339 6/1/12 9:52 AM Part 4 Gravimetric Unit ACTH pg/mL Albumin μg/dL g/dL Aldosterone, S ng/dL Aldosterone, U μg/24 h Alkaline Phosphatase, Bone Specific μg/L Alpha Subunit ng/mL 3α-Androstanediol Glucuronide ng/dL Androstenedione ng/dL Angiotensin Converting Enzyme U/L Angiotensin II ng/L 1,5-Anhydroglucitol (1,5-AG) μg/mL Anti-Müllerian Hormone ng/mL Apolipoprotein A1 mg/dL Apolipoprotein B mg/dL Arginine Vasopressin pg/mL B-Type Natriuretic Peptide pg/mL C-peptide, 24-h U μg/g creat C-Peptide, S ng/mL Calcitonin pg/mL Calcium, Ionized mg/dL Calcium, S mg/dL Calcium, U mg/24 h mg/g creat mg/mg creat Catecholamines, P Epinephrine pg/mL Norepinephrine pg/mL Dopamine pg/mL Catecholamines, U Epinephrine μg/24 h Norepinephrine μg/24 h Dopamine μg/24 h Epinephrine μg/g creat Norepinephrine μg/g creat Dopamine μg/g creat Cholesterol, HDL mg/dL Cholesterol, HDL Subclasses mg/dL Cholesterol, LDL, Direct mg/dL Analyte Conversion Factor 0.22 0.01 10 0.0277 2.77 1.0 1.0 0.0213 0.0349 0.017 1.0 6.0918 7.1429 0.01 0.01 0.926 1.0 0.0377 0.333 1.0 0.25 0.25 0.025 2.828 2.828 International Unit pmol/L mg/L g/L nmol/L nmol/d μg/L μg/L nmol/L nmol/L μKat/L ng/L μmol/L pmol/L g/L g/L pmol/L ng/L nmol/mmol creat nmol/L ng/L mmol/L mmol/L mmol/d mmol/mol creat mmol/mmol creat 5.454 5.914 6.524 pmol/L pmol/L pmol/L 5.454 5.914 6.524 0.617 0.669 0.738 0.0259 0.0259 0.0259 nmol/d nmol/d nmol/d μmol/mol creat μmol/mol creat μmol/mol creat mmol/L mmol/L mmol/L S, serum; U, urine; P, plasma; ACTH, adrenocorticotropic hormone. 340 86270_Endocrinology_P4.indd 340 6/1/12 9:52 AM International System of Units (SI Units) Conversion Factor 0.0259 1.0 1.0 1.0 0.0289 1.0 17.18 27.6 2.76 0.3122 27.6 0.0277 2.774 88.4 8.84 1.0 1.0 0.0303 0.0289 25.48 0.0347 0.0035 0.3922 0.0271 0.0344 3.440 3.67 3.67 1.0 International Unit mmol/L μg/L nmol BCE/ mmol creat ng/L nmol/L ng/L nmol/L nmol/L nmol/d μmol/mol creat nmol/L μmol/L mmol/d μmol/L mmol/d μmol/L mg/L nmol/L nmol/L pmol/L nmol/L μmol/d μmol/mol creat μmol/L nmol/L pmol/L pmol/L pmol/L ng/L 3.699 3.67 3.47 3.699 2.730 1.0 1.0 pmol/L pmol/L nmol/L pmol/L pmol/L μmol/L IU/L SI Units Gravimetric Unit Cholesterol, Total mg/dL Chromogranin A ng/mL Collagen Cross-Linked nmol BCE/ N-Telopeptide (NTx) mmol creat Collagen Type 1 C-Telopeptide (CTx) pg/mL Corticosterone ng/dL Corticotropin Releasing Hormone pg/mL Cortisol Binding Globulin mg/L Cortisol, Free, S μg/dL Cortisol, Free, U μg/24 h μg/g creat Cortisol, S and Saliva μg/dL Cortisone, S μg/dL Cortisone, U μg/24 h Creatinine mg/dL g/24 h Cyclic AMP, Urine nmol/mL Cystatin C mg/L Deoxycorticosterone ng/dL 11-Deoxycortisol ng/dL Dexamethasone ng/dL DHEA ng/dL μg/24 h μg/g creat DHEA Sulfate μg/dL Dihydrotestosterone ng/dL Dihydrotestosterone, Free pg/mL Estradiol (E2), Free pg/mL Estradiol (E2), S pg/mL Estrogen, Total, S pg/mL Estrogens, Fractionated, S Estrone pg/mL Estradiol pg/mL Estriol ng/mL Estrone (E1), S pg/mL Estrone Sulfate pg/mL Fructosamine μmol/L FSH mIU/mL Analyte S, serum; U, urine; P, plasma; DHEA, dehydroepiandrosterone; FSH, follicle stimulating hormone. 341 86270_Endocrinology_P4.indd 341 6/1/12 9:52 AM Part 4 Analyte GAD-65 Antibodies Gastrin Glucagon Glucose, S Growth Hormone Growth Hormone Binding Protein hCG, Beta Subunit hCG, Total 5-HIAA Histamine Plasma or whole blood Urine Homovanillic Acid 17-Hydroxycorticosteroids 18-Hydroxycorticosterone 6β-Hydroxycortisol 18-Hydroxycortisol 21-Hydroxylase Antibody 17-Hydroxypregnenolone 17-Hydroxyprogesterone Hydroxyproline Hyperglycosylated hCG (h-hCG) IA-2 Antibody IGFBP-1 IGFBP-2 IGFBP-3 IGF-I IGF-II Inhibin A Inhibin B Insulin Antibodies Insulin, Free Insulin, Total Gravimetric Unit U/mL pg/mL pg/mL mg/dL ng/mL pmol/L mIU/mL mIU/mL mg/24 h mg/g creat Conversion Factor 1.0 1.0 1.0 0.0555 1.0 1.0 1.0 1.0 5.23 0.592 International Unit kU/L ng/L ng/L mmol/L μg/L pmol/L IU/L IU/L μmol/d μmol/mmol ng/mL μg/g creat mg/24 h mg/24 h mg/g creat mg/24 h mg/g creat ng/dL μg/24 h μg/24 h U/mL ng/dL ng/dL mg/dL pg/mL U/mL ng/mL ng/mL mg/L ng/mL ng/mL pg/mL pg/mL U/mL μIU/mL μIU/mL 8.997 1.018 8.997 5.49 0.621 2.76 0.312 0.0276 2.642 2.642 1.0 0.0301 0.0303 76.3 0.0255 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 7.175 7.175 nmol/L nmol/mmol creat μmol/d μmol/d μmol/mmol creat μmol/d mmol/mol creat nmol/L nmol/d nmol/d kU/L nmol/L nmol/L μmol/L pmol/L kU/L μg/L μg/L mg/L μg/L μg/L ng/L ng/L kU/L pmol/L pmol/L S, serum; U, urine; P, plasma; GAD-65, glutamic acid decarboxylase-65; hCG, human chorionic gonadotropin; 5-HIAA, 5-hydroxyindoleacetic acid; IGFBP, IGF binding protein; IGF, insulin-like growth factor. 342 86270_Endocrinology_P4.indd 342 6/1/12 9:52 AM International System of Units (SI Units) Conversion Factor 3.47 0.392 1.0 1.0 0.01 1.0 0.4114 0.0411 4.6542 International Unit μmol/d μmol/mmol creat μg/L IU/L g/L μg/L mmol/L mmol/d mmol/mol creat pg/mL pg/mL pg/mL 5.07 5.46 5.26 pmol/L pmol/L pmol/L Osmolality, S μg/24 h μg/24 h μg/24 h μg/g creat μg/g creat μg/g creat mg/24 h μg/min mg/g creat μg/mg creat mOsm/kg 5.07 5.46 5.26 0.574 0.617 0.595 1.0 1.0 0.113 0.113 1.0 Osmolality, U mOsm/kg 1.0 nmol/d nmol/d nmol/d nmol/mmol creat nmol/mmol creat nmol/mmol creat mg/d μg/min mg/mmol creat μg/μmol creat mmol osmotically active particles/kg H2O mmol osmotically active particles/kg H2O μg/L μg/L ng/L μg/L/h ng/L•s mg/L nmol/d μmol/mol creat nmol/L nmol/L 17-Ketosteroids Leptin LH (Luteinizing Hormone) Lipoprotein (a) Macroprolactin Magnesium, S Magnesium, U Metanephrines, P Metanephrine Normetanephrine Total Metanephrines, U Metanephrine Normetanephrine Total Metanephrine Normetanephrine Total Microalbumin, U Osteocalcin ng/mL ng/dL Pancreatic Polypeptide pg/mL Plasma Renin Activity (PRA) ng/mL/h ng/mL/h Prealbumin μg/dL Pregnanetriol μg/24 h μg/g creat Pregnenolone ng/dL Procollagen Type I Intact N-Terminal μg/L Propeptide 1.0 0.01 1.0 1.0 0.2778 0.01 2.97 0.336 0.0316 0.0286 SI Units Gravimetric Unit mg/24 h mg/g creat ng/mL mIU/mL mg/dL ng/mL mg/dL mg/24 h mg/g creat Analyte S, serum; U, urine; P, plasma. 343 86270_Endocrinology_P4.indd 343 6/1/12 9:52 AM Part 4 Analyte Progesterone Proinsulin Prolactin Prolactin, Monomeric PTH, Intact PTH-Related Protein (PTH-RP) Serotonin Sex Hormone Binding Globulin Somatostatin T3, Free T3, Reverse T3, Total T4, Free T4, Total TBG Testosterone, Bioavailable Testosterone, Free Testosterone, Total Testosterone, Urine Tetrahydroaldosterone Thyroglobulin Thyroglobulin Antibody Thyroid Peroxidase Antibody (Anti-TPO) Thyroid Stimulating Hormone (TSH) Triglycerides Vasoactive Intestinal Polypeptide Vitamin D2 (Ergocalciferol) Vitamin D, 1,25-Dihydroxy Vitamin D, 25-Hydroxy VMA, Urine Gravimetric Unit ng/mL ng/dL pg/mL ng/mL ng/mL pg/mL pg/mL ng/mL nmol/L pg/mL pg/dL pg/mL ng/dL ng/dL ng/dL μg/dL μg/mL ng/dL pg/mL ng/dL μg/24 h μg/g creat μg/24 h μg/g creat ng/mL IU/mL Conversion Factor 3.18 0.0318 0.1134 0.04348 0.04348 0.1061 1.0 5.675 1.0 0.611 0.0154 1.5362 0.0154 0.0154 12.87 12.87 0.0185 0.0347 3.47 0.0347 3.47 0.3922 1.0 0.113 1.0 1.0 International Unit nmol/L nmol/L pmol/L nmol/L nmol/L pmol/L ng/L nmol/L nmol/L pmol/L pmol/L pmol/L nmol/L nmol/L pmol/L nmol/L μmol/L nmol/L pmol/L nmol/L nmol/d μmol/mol creat μg/d μg/mmol creat μg/L kIU/L IU/mL mIU/L mg/dL pg/mL ng/mL pg/mL ng/mL mg/24 h mg/g creat 1.0 1.0 0.0113 1.0 2.5211 2.400 2.496 5.05 0.571 kIU/L mIU/L mmol/L ng/L nmol/L pmol/L nmol/L μmol/d mmol/mol creat S, serum; U, urine; P, plasma; TBG, thyroxine binding globulin; VMA, vanillylmandelic acid. 344 86270_Endocrinology_P4.indd 344 6/1/12 9:52 AM
