Fogh-Andersen N, D'Orazio P
Department of Clinical Biochemistry, Herlev Hospital, Denmark.
Clin Chem. 1998 Mar;44(3):655-9.
Direct-reading glucose biosensors sense molality (glucose per unit water mass) in the sample. With aqueous calibration, a direct-reading glucose biosensor produces higher results in blood and plasma than methods measuring concentration, theoretically by the ratio of water concentrations in calibrator and sample. To confirm this, we measured glucose in 14- blood and 40 plasma samples with the direct-reading glucose sensor in the Chiron Model 860 Blood Gas and Critical Analyte System and with our routine method (ESAT 6660; Eppendorf). The Chiron instrument is calibrated with a 10 mmol/L (180 mg/dL0 glucose calibrator (mass concentration of water = 0.99 kg/L). Assuming normal water concentrations of 0.84 and 0.93 kg/L in blood and plasma, respectively, we multiplied results from the Chiron sensor by 0.84/0.99 and 0.93/0.99 to obtain concentrations in blood and plasma. This conversion resulted in agreement of results with our routine method. An individual conversion based on hematocrit in each whole-blood sample was less satisfactory. To avoid confusion over variously measured and reported glucose results and reference values, we suggest standardization and reporting of whole-blood glucose results as equivalent plasma concentrations. This proposal may be conveniently achieved by using a commercially available reference material for glucose, NIST SRM 965.
直读式葡萄糖生物传感器可检测样品中的质量摩尔浓度（每单位水质量中的葡萄糖）。通过水溶液校准，直读式葡萄糖生物传感器在血液和血浆中得出的结果高于测量浓度的方法，理论上是由于校准液和样品中水浓度的比例不同。为了证实这一点，我们使用Chiron Model 860血气和危急分析物系统中的直读式葡萄糖传感器以及我们的常规方法（ESAT 6660；Eppendorf）测量了14份血液和40份血浆样品中的葡萄糖。Chiron仪器用10 mmol/L（180 mg/dL）的葡萄糖校准液（水的质量浓度 = 0.99 kg/L）进行校准。假设血液和血浆中水的正常浓度分别为0.84和0.93 kg/L，我们将Chiron传感器得出的结果分别乘以0.84/0.99和0.93/0.99，以获得血液和血浆中的浓度。这种转换使结果与我们的常规方法相符。基于每个全血样品的血细胞比容进行单独转换的效果不太理想。为避免因葡萄糖结果和参考值的测量与报告方式不同而产生混淆，我们建议将全血葡萄糖结果标准化并报告为等效血浆浓度。使用市售的葡萄糖参考物质NIST SRM 965可方便地实现这一建议。
