Chapter 708 Reference Intervals for Laboratory Tests and Procedures
In Tables 708-1 through 708-6 (found on the Nelson Textbook of Pediatrics website at www.expertconsult.com 
), the reference intervals apply to infants, children, and adolescents when possible. For many analyses, however, separate reference intervals for children and adolescents are not well delineated. When interpreting a test result, the reference interval supplied by the laboratory performing the test should always be used as these intervals are instrument and/or method dependent. See Figures 708-1 to 708-3 (also located on the Nelson Textbook of Pediatrics website at www.expertconsult.com 
) for estimations related to dosages.
Table 708-1 PREFIXES DENOTING DECIMAL FACTORS
| PREFIX | SYMBOL | FACTOR |
|---|---|---|
| Mega- | M | 106 |
| Kilo- | k | 103 |
| Hecto- | h | 102 |
| Deka- | da | 101 |
| Deci- | d | 10−1 |
| Centi- | c | 10−2 |
| Milli- | m | 10−3 |
| Micro- | µ | 10−6 |
| Nano- | n | 10−9 |
| Pico- | p | 10−12 |
| Femto- | f | 10−15 |
| Ab | Absorbance |
| AU | Arbitrary unit |
| BB | Brain isoenzyme of creatine kinase |
| cap | Capillary |
| CH50 | Dilution required to lyse 50% of indicator red blood cells; indicates complement activity |
| Cr | Creatinine |
| CSF | Cerebrospinal fluid |
| F | Female |
| g | Gram |
| hr | Hour, hours |
| Hb | Hemoglobin |
| HbCO | Carboxyhemoglobin |
| hpf | High-power field |
| IU | International unit of hormone activity |
| L | Liter |
| M | Male |
| MB | Heart isoenzyme of creatine kinase |
| mEq/L | Milliequivalents per liter |
| min | Minute, minutes |
| mm3 | Cubic millimeter, microliter (µL) |
| mm Hg | Millimeters of mercury |
| mo | Month, months |
| mol | Mole |
| mmol | Millimole |
| mOsm | Milliosmole |
| MW | Relative molecular weight |
| ND | Not detected |
| nm | Nanometer (wavelength) |
| Pa | Pascal |
| pc | Postprandial |
| RBC |
