Measuring Whole Blood Glucose or Plasma Glucose
HemoCue® Glucose systems are used for determination of the total amount of glucose in whole blood. The result can be displayed in either whole blood or as a plasma equivalent result.
The HemoCue® plasma equivalent glucose systems report glucose values based on the 2001 recommendation of the International Federation of Clinical Chemistry1. This recommendation was to report glucose results as plasma glucose, regardless of sample type or technology. Whole blood values, which are physiologically different from plasma values, should be converted to plasma equivalent values by multiplying by a constant factor of 1.11. This factor is based on the relationship between plasma and whole blood glucose at normal hematocrit (0.43).
Glucose is dissolved in water. The plasma phase of blood has a higher concentration of water (~93%) compared to that of red blood cells (~71%). Therefore plasma has a higher glucose concentration than that of whole blood. The difference in glucose concentration will vary with the hematocrit; the lower the hematocrit the smaller the difference, and the higher the hematocrit the larger the difference between the two sample types.
In laboratories glucose is generally measured on plasma, after removal of the blood cells by centrifugation, while at the point of care (POC) the measurement is made on whole blood. Glucose values from the laboratory and POC are often used interchangeably. If the clinical staff is unaware of the difference between plasma and whole blood glucose values, there is a risk of clinical misinterpretation. In an attempt to resolve this problem the International Federation of Clinical Chemistry issued their recommendation on
reporting results for blood glucose.
1. International Federation of Clinical Chemistry and Laboratory Medicine, Scientific Division, Working Group on Selective Electrodes IFCC recommendation on reporting results for blood glucose. Clinica Chimica Acta 307; 2001, 205–209.
Do you want to know more? For further information, please contact HemoCue®.
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