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Clinical Laboratory Values
ОглавлениеThere are two systems for reporting clinical data either in conventional units or International Units (SI). The preferred method for reporting clinical laboratory data is in terms of International Units (SI Units). "SI Units" term is an abbreviation for le Système International d’Unités or International System. The reason for the change to SI units is to have an international standard for reporting research and medical data.
Laboratory Assessment of Nutritional Status: Bridging Theory & Practice provides both conventional units and SI units since both are used widely. Table 2 includes conversion factors for selected laboratory tests.
| Conventional Units can be converted to SI Units using this formula: |
| Conventional Units x conversion factor = SI Unit |
| SI Units can be converted to Conventional Units using this formula: |
| SI Unit ÷ conversion factor = Conventional Unit |
Table 2 provides conversion factors for selected values in Clinical Chemistry.
Table 2. Selected SI Units & Conversion Table for Values in Clinical Chemistry
| Component | Conventional Reference values/ Units | Conversion factor | SI Reference Values/ Units |
| Alanine Aminotransferase (ALT) (S) | 5-40 U/L | 1.0 | 5-40 U/L |
| Albumin (S) | 3.5-5.0 g/dL | 10.0 | 35-50 g/L |
| Alkaline Phosphatase (S) | 35-112 U/L | 0.01667 | 0.5-2.0 μkat/L |
| Ammonia (vP) | 10-80 mcg/dL | 0.5909 | 6-47 μmol/L |
| Aspartate Aminotransferase (AST) (S) | 0-35 U/L | 0.01667 | 0.0-0.58 μkat/L |
| Bilirubin, total (S) | 0.1-1.2 mg/dL | 17.10 | 2-20 μmol/L |
S = Serum, B = Blood, P = Plasma, U = Urine
Table 2. Selected SI Units & Conversion Table for Values in Clinical Chemistry
| Component | Conventional Reference values/ Units | Conversion factor | SI Reference Values/ Units |
| Bilirubindirect (S) | 0.0-0.2 mg/dL | 17.10 | 0.0-4.0 μmol/L |
| Calcium (S) | 8.6-10.3 mg/dL | 0.2495 | 2.15-2.57 mmol/L |
| Chloride (S) | 98-108 mEq/L | 1.00 | 98-108 mmol/L |
| Cholesterol (P) | <200 mg/dL | 0.02586 | <5.15 mmol/L |
| Creatinine (S) Males Females | 0.6-1.2 mg/dL 0.5-1.1 mg/dL | 88.40 88.40 | 53-106 μmol/L 44-97 μmol/L |
| Creatinine (U) | Variable g/24 hr | 8.840 | Variable mmol/L |
| Cyanocobalamin (S) (Vitamin B12) | 250-950 pg/mL | 0.7378 | 118-701 pmol/L |
| Ferritin (S) Males Females | 29-438 ng/mL 9-219 ng/mL | 1.00 1.00 | 29-438 μg/dL 9-219 μg/dL |
| Folate (S) | 2.5-20 ng/mL | 2.266 | 6-46 nmol/L |
| Glucose (P) fasting | 70-100 mg/dL | 0.05551 | 3.9-5.5 mmol/L |
| Hematocrit volume fraction Female Male | 37-47% 42-52% | 0.01 0.01 | 0.37-0.47 0.42-0.52 |
| Hemoglobin (B) Male Female | 14-18 g/dL 12-16 g/dL | 0.6214 0.6214 | 8.7-11.2 mmol/L 7.4-9.9 mmol/L |
| Iron (S) Male Female | 80-180 mcg/dL 60-160 mcg/dL | 0.1791 0.1791 | 14-32 μmol/L 11-29 μmol/L |
Table 2. Selected SI Units & Conversion Table for Values in Clinical Chemistry
| Component | Conventional Reference values/ Units | Conversion factor | SI Reference Values/ Units |
| Iron binding capacity | 230-410 mcg/dL | 0.1791 | 41-73 μmol/L |
| Lactate dehydrogenase (S) | 120-300 U/L | 1 | 120-300 U/L |
| Lipoproteins (P) low density (LDL) high density (HDL) | <100 mg/dL > 40 <60 mg/dL | 0.02586 0.02586 | < 2.59 mmol/L >1.0 < 1.55 mmol/L |
| Mean corpuscular hemoglobin concentration (MCH) mass | 27-31 pg | 1 | 27-31 pg |
| MCV (MCV) | 80-100 um3 (microns3) | 1 | 80-100 fL |
| Mean corpuscular hemoglobin concentration (MCHC) | 32-36 % | 0.01 | 0.32-0.36 |
| Osmolality (P) | 278-300 mOsm/kg H2O | 1.00 | 278-300 mmol/kg H2O |
| Osmolality (U) Random | Varies mOsm/kg | 1.00 | Varies mmol/kg |
| Phosphate (S) | 2.3-4.1 mg/dL | 0.3229 | 0.75-1.35 mmol/L |
| Potassium ion (S) | 3.7-5.1 mEq/L | 1.00 | 3.7-5.1 mmol/L |
| Sodium ion (S) | 134-142 mEq/L | 1.00 | 134-142 mmol/L |
Table 2. Selected SI Units & Conversion Table for Values in Clinical Chemistry
| Component | Conventional Reference values/ Units | Conversion factor | SI Reference Values/ Units |
| Thyroid-stimulating hormone (TSH) | 0-5 μIU/mL | 1.0 | 0-5 mIU/L |
| Thyroxine T4 Male Female | 4.0-12.0 mcg/dL 5.0-12.0 mcg/dL | 12.87 12.87 | 51-154 nmol/L 64-154 nmol/L |
| Triiodothyronine T3 | 70-235 ng/mL | 0.01536 | 1.1-3.6 nmol/L |
| Transferrin (S) Male Female | 215-365 mg/dL 250-380 mg/dL | 0.01 0.01 | 2.15-3.65 g/L 2.50-3.80 g/L |
| Triglycerides (S) | <100 mg/dL | 0.01129 | <1.13 mmol/L |
| Urea nitrogen (S) | 6-25 mg/dL | 0.3570 | 2.1-8.9 mmol/L |
S = Serum, B = Blood, P = Plasma, U = Urine
Adapted from Fischbach,F A Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia, PA, Lippincott, Williams & Wilkins
Laboratory Assessment of Nutritional Status: Bridging Theory & Practice uses a variety of standard abbreviations and units of measurement listed in Table 3. Many organizations are moving away from the use of lower case Greek letters such as μ for micro to avoid miscommunication. Please note that your institutional policy on standard abbreviations and units of measurement may vary.
Table 3. Abbreviations & Units of Measurement
| Abbreviation | Definition | Abbreviation | Definition |
| < | Less than | kg H2O | Kilogram of water |
| < | Less than or equal to | L | Liter |
| > | Greater than | m | Meter |
| > | Greater than or equal to | m2 | Square meter |
| AU | Arbitrary units | m3 | Cubic meter |
| C | Celsius | mcg | Microgram |
| cc | Cubic centimeter | μmol | Micromole |
| cg | Centigram | mEq | Milliequivalent |
| cm | Centimeter | mEq/L | Milliequivalent per liter |
| cm H2O | Centimeter of water | mg | Milligram |
| cu | Cubic | min | Minute |
| dL | Deciliter (100 mL) | mL | Milliliter |
| fl | Femtoliter | mm | Millimeter |
| fmol | Femtomole | mm3 | Cubic millimeter |
| g or gm | Gram | mM | Millimole |
| h | Hour | mm Hg | Millimeter of mercury |
| IU | International Unit | mm H2O | Millimeter of water |
| ImU | International milliunit | mol | Mole |
| ImcU | International microunit | mmol | Millimole |
| IU | International Unit | mOsm | Milliosmole |
| K | Kilo | mμ | Millimicron |
| kat | Katal | mU | Milliunit |
| kg | Kilogram | mμ | Millimicron |
