Evaluation of a lactate sensor for rapid repeated measurements of blood lactate concentration

In critically ill patients, serial measurements of blood lactate may indicate adequacy of therapy and predict development of multi-organ failure. We studied the accuracy, precision, and repeatability of the newly developed 800 Series Lactate Sensor (Ciba Corning Diagnostic Corp., Medfield, U.S.A.). Lactate levels determined with the sensor were compared with the standard laboratory method (Abbott TDX) in 75 paired arterial blood samples from 20 patients. Agreement between methods was determined and the mean coefficient of variation calculated for repeated measurements. The bias of the sensor was -0.38 mmol/l (CI -0.23 to -0.53), and the precision +/- 0.67. The coefficient of variation for repeated measurements was 1.95% with the sensor, and 11.5% with the TDX (P = 0.007). The new sensor offers a more reproducible, rapid method of measuring lactate, vital for serial measurements. The relatively wide limits of agreement between the methods reflect the greater variability of the TDX assay.