Validation of a hand-held lactate device in determination of blood lactate in critically injured patients.

OBJECTIVES: Admission blood lactate is an accurate predictor of injury severity and mortality in trauma patients. The purpose of this study was to evaluate a portable lactate analyzer in a clinical setting by patient care staff. DESIGN: A prospective, single-operator control solution and patient sample study, using two test devices and a reference device. SETTING: An urban Level I trauma center. PATIENTS: A convenience sample of 47 trauma patients. INTERVENTIONS: Intra-assay precision was demonstrated by performance of consecutive analyses of two lactate control solutions (high and low lactate control concentrations) by medical students and physicians. Split sample, simultaneous testing of the portable lactate analyzer was then performed on 66 whole blood specimens from a convenience sample of 47 trauma patients admitted to an urban Level 1 trauma center over 4 mos. Samples were tested simultaneously tested on two portable lactate analyzers and a reference instrument. MEASUREMENTS AND MAIN RESULTS: Acceptable intra-assay precision was achieved. Regression analysis for two test instruments demonstrated a slope of 0.920, an intercept of 0.323, an r2 of .982, and an SEM of 0.496. Regression analysis for test instrument "A" vs. the reference instrument showed a slope of 0.861, an intercept of 0.209, an r2 of .977, and an SEM of 0.598. Regression analysis for test instrument "B" vs. the reference instrument demonstrated a slope of 0.929, an intercept of -0.095, an r2 of .983, and an SEM of 0.506. CONCLUSIONS: Good correlation with a low SEM was obtained over a wide range of clinically relevant lactate values. Use of point of care lactate analysis will decrease analytic time, making an important diagnostic parameter immediately available in the critical care setting.

Analysis of alpha-fetoprotein by a procedure combining crossed immunoaffinoelectrophoresis and immunoblotting.

A newly developed procedure combining crossed immunoaffinoelectrophoresis and an immunoblotting assay (CIAE-IBA) has been used to discriminate between and precisely quantitate lectin-bound and lectin-free forms of alpha-fetoprotein (AFP) derived from human serum at levels of AFP as low as 5.6 ng/ml (adult reference range, 0 to 15). Twenty-two serum specimens with elevated levels of AFP were examined by a reference CIAE method, using either of two lectins, concanavalin A (Con A) or Lens culinaris agglutinin (LCA); aliquots of the specimens were then diluted in AFP-free serum to normal or near-normal levels of AFP and examined by CIAE-IBA, which included a final protein transfer to nitrocellulose. The quantitative results produced by the two methods were essentially the same. Overall, the sensitivity of the CIAE-IBA procedure surpasses that of other CIAE methods of AFP fractionation. The CIAE-IBA procedure may be used for study of the heterogeneity of AFP and may be applicable as well to the study of other proteins.

Analysis of alpha-fetoprotein heterogeneity by an improved crossed immunoaffinoelectrophoretic technique.

The crossed immunoaffinoelectrophoretic procedure described here for the analysis of alpha-fetoprotein heterogeneity includes three major modifications of a procedure previously used by others: impregnation of the second dimension gel with methylated sugar derivatives; rigorous gel washing at 37 degrees C with the same derivatives; and an immunostaining technique. These simple changes have resulted in clear, sharp electrophoretic patterns at levels of total alpha-fetoprotein as low as 50 ng/ml, a sensitivity not previously approached with the method. Individual peaks representing as little as 7.5 ng/ml can be identified.