Manual of basic techniques for a health laboratory - libdoc.who.int

1. Introduction 7Table 1.5 (cont.)Quantity name SI unit Traditional quantity Traditional unit Conversion factors and examples anameThrombocyte number no. ¥ 10 9 /l platelet count no./mm 3 220 000/mm 3 ¥ 0.001 = 220 ¥ 10 9 /lconcentration (see 250 ¥ 10 9 /l ¥ 1000 = 250 000/mm 3section 9.14)Glucose, substance mmol/l glucose, mass mg/100 ml 81 mg/100 ml ¥ 0.0555 = 4.5 mmol/lconcentration concentration c (blood 4.2 mmol/l ¥ 18.02 = 75.7 mg/(blood and CSF) and CSF) 100 ml(see sections 10.1 and 8.3.4)Haemoglobin (Fe), mmol/l haemoglobin, mass g/100 ml Hb 13.7 g/100 ml ¥ 0.621 = Hb(Fe)substance concentration concentration c 8.5 mmol/l(see section 9.3) Hb(Fe) 9 mmol/l ¥ 1.61 = Hb 14.5g/100 mlHaemoglobin, mass g/l haemoglobin, mass g/100 ml 14.8 g/100 ml ¥ 10 = 148 g/lconcentration concentration c 139 g/l ¥ 0.1 = 13.9 g/100 ml(see section 9.3)Mean erythrocyte mmol/l mean corpuscular % e 35% ¥ 0.621 = 21.7 mmol/lhaemoglobin (Fe) substance haemoglobin 22 mmol/l ¥ 1.611 = 35.4%concentrationconcentration (i.e. mass(see section 9.4)concentration) dMean erythrocyte g/l mean corpuscular % e 35% ¥ 10 = 350 g/lhaemoglobin mass haemoglobin 298 g/l ¥ 0.1 = 29.8%concentration (see sectionconcentration (i.e. mass9.4) concentration)Protein, mass concentration g/l protein, mass mg/100 ml 25 mg/100 ml ¥ 0.01 = 0.25 g/l(CSF) (see section 8.3.5) concentration c 0.31 g/l ¥ 100 = 31 mg/100 mlg/lNo changeUrea, substance mmol/l urea, mass mg/100 ml 15 mg/100 ml ¥ 0.167 = 2.5 mmol/lconcentration (blood) concentration c 2.9 mmol/l ¥ 6.01 = 17.4 mg/100 ml(see section 10.2) urea nitrogen, e mass mg/100 ml urea nitrogen 7 mg/100 mlconcentration¥ 0.357 = urea 2.5 mmol/lCSF: cerebrospinal fluid.aThe examples show first the conversion of actual numerical values in traditional units into values in SI units, and then the conversion from SIinto traditional units. The conversion factor is underlined.bIn this case, the number fraction is reported not as a fraction of 1, but as a fraction of 1000, in order to avoid inconveniently small numericalvalues.cMass concentration is what was measured, but the term “mass concentration” was not usually used.dMean corpuscular haemoglobin concentration was sometimes expressed as a decimal fraction rather than a percentage, e.g. 0.35 instead of35%. In this case, each of the conversion factors listed must be multiplied or divided by 100, as in the following examples:0.35 ¥ 62.1 = 21.7 mmol/l22 mmol/l ¥ 0.01611 = 0.3540.35 ¥ 1000 = 350 g/l298 g/l ¥ 0.001 = 0.298eIn the traditional system urea was sometimes reported in terms of urea and sometimes in terms of urea nitrogen (i.e. the nitrogen content ofthe urea).