CLINICAL LAB SCIENEC

CHAPTER 9: LABORATORY MATHEMATICS 215
of the measured material (analyte) per liter. Sometimes a facility will report the
values in both denominations, but conversion from the previously-used method
to the SI units is possible. With global relationships in business and in medicine,
as well as differences in the reporting of values even in the United States, it is
necessary to become familiar with the two basic methods of reporting values,
particularly in chemistry tests. The clinical laboratory worker may be considered
as a valuable reference resource for explaining the units used for reporting the
various values. Sometimes report forms will document the results of laboratory
procedures in both denominations. Values frequently encountered in the SI system
are shown in Tables 9-6 and 9-7.
Table 9-5 Temperature Conversion Chart, Fahrenheit to Celsius
ºF ºC ºF ºC ºF ºC ºF ºC ºF ºC ºF ºC
32 0 90 32.2 100 37.8 105 40.6 110 43.3 115 46.1
70 21.1 95 35 101 38.3 106 41.1 111 43.9 116 46.7
75 23.9 97 36.1 102 38.9 107 41.7 112 44.4 117 47.2
80 26.7 98.6 37.0 103 39.4 108 42.2 113 45 118 47.8
85 29.4 99 37.2 104 40 109 42.8 114 45.6 119 48.3
NOTE: 98.6ºF and 37ºC = normal (average) body temperature of a human.
Table 9-6 Values in the SI System
Blood cell counts are sometimes reported by both units of measurement.
Previously Used Nomenclature
SI System Nomenclature
Micron (μm)
Micrometer (μm), or 10 –6 m (meter)
Cubic micron (formerly used for blood cell size)
Femtoliter (fL) or 10 –15 L
Angstrom
Nanometer (nm) or ×10 –9 m
Lambda
Microliter (μL) or 10 –6 L
Table 9-7 Examples of SI Units in Blood Cell Counts
Example of reporting a complete blood count with red blood cell (RBC) indices (size and concentration
of hemoglobin).
Constituent Conventional Unit SI Unit
Red and white cell counts #/cu. mm (mm 3 ) Cells/microliter or liter
Hematocrit (% of red cells/whole blood) Percentage, i.e., 36% Decimal, i.e., .36
Hemoglobin g/dL g/L
MCV (mean corpuscular volume) μ 3 fL
MCH (mean corpuscular hemoglobin) Uμg pg
MCHC (mean corpuscular hemoglobin concentration) % g/dL or g/L
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