Novel In-Line Hemolysis Detection on a Blood Gas Analyzer and Impact on Whole Blood Potassium Results.

BACKGROUND: Preanalytical error due to hemolyzed blood samples is a common challenge in laboratory and point-of-care (POC) settings. Whole blood potassium (K+) measurements routinely measured on blood gas analyzers are particularly susceptible to hemolysis, which poses a risk for incorrect K+ results. The GEM Premier 7000 with IQM3 (GEM 7000) blood gas analyzer provides novel integrated hemolysis detection within the sample measurement process. Therefore, the GEM 7000 can detect and flag hemolyzed whole blood samples at the POC, warning the operator of potentially erroneous results. METHODS: Heparinized venous or arterial whole blood samples were used for K+ interference studies and assessed for hemolysis agreement utilizing either a traditional volumetric method or chemistry analyzer serum index measurements with the Roche cobas c311 or Abbott Alinity c. RESULTS: Hemolysis interference studies performed at 2 different K+ concentrations (3.8 and 5.3 mmol/L) identified that a plasma free hemoglobin ≥116 mg/dL can impact K+ results on the GEM 7000. Hemolysis agreement studies demonstrated an excellent agreement of >99% with the volumetric method, 98.8% with cobas H index, and 96.4% with Alinity H index. GEM 7000 K+ results were correctly flagged for both native and spiked samples. CONCLUSION: GEM 7000 hemolysis detection provides a novel technology to detect hemolysis in whole blood samples. Moreover, the GEM 7000 demonstrates excellent agreement with traditional laboratory hemolysis detection methods and offers an integrated technological solution for assuring the quality of whole blood K+ results in POC settings.

Clinical Evaluation of a New Point-of-Care System for Chemistry Panel Testing.

BACKGROUND: GEM Premier ChemSTAT™ is a point-of-care (POC) system that measures Na+, K+, Ca++, Cl-, glucose, hematocrit, creatinine, blood urea nitrogen (BUN), tCO2, pH, pCO2, and lactate from a single whole blood specimen, providing rapid results in POC settings such as the emergency department (ED). Accurate measurements of creatinine in whole blood and reporting of estimated glomerular filtration rate (eGFR) can minimize adverse effects of contrast-induced nephropathy. METHODS: Heparinized whole blood specimens from the ED were analyzed on the ChemSTAT by POC staff. Method comparison was performed against the cobas Integra c501 for creatinine, BUN, and tCO2, and against the GEM Premier 4000 for all other analytes. Precision was conducted with whole blood specimens assayed in triplicate over 6 days. Creatinine results from whole blood and plasma were used for eGFR, by isotope dilution mass spectrometry-traceable Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations, and eGFR concordance was assessed. RESULTS: Creatinine, BUN, and tCO2 correlated well with plasma samples on the cobas, and all other analytes correlated well with whole blood specimens on the GEM Premier 4000 across the tested sample ranges. The regression slope was 0.951 to 1.047, along with a correlation coefficient (r) of ≥0.982 for all analytes. The pooled within-sample precision was 0% to 2.5% for all analytes. CONCLUSIONS: ChemSTAT demonstrated a strong correlation with the comparative methods and excellent precision. The system's analytical performance and continuous quality management make it suitable for use in the ED to provide rapid reliable test results, which could minimize the time to treatment and improve ED efficiency.

Hydroxocobalamin and cyanocobalamin interference on co-oximetry based hemoglobin measurements.

BACKGROUND: Hydroxocobalamin (OHCbl) and cyanocobalamin (CNCbl) are dark-red colored analogs of vitamin B-12. OHCbl is used as an alternate antidote for cyanide poisoning. Due to the strong red color, if uncorrected, these cobalamins interfere with hemoglobin measurements and can introduce errors in spectrophotometric assay on co-oximeters. The impact of cobalamins on commonly used co-oximetry systems was compared to evaluate the accuracy of hemoglobin measurements and to further assess the ability of the instruments to detect and flag cobalamin interference. METHODS: Blood samples spiked with varying concentrations of hydroxocobalamin or cyanocobalamin (0-2 g/l), were measured on 3 GEM Premier 4000 s, 3 IL 682 CO-Oximeter, 1 Radiometer ABL 735 and 1 Siemens Rapidpoint 405 analyzer. The effect of OHCbl or CNCbl interference on total hemoglobin and hemoglobin derivatives is evaluated using the measured difference between the control sample and the spiked sample. RESULTS: Spectral measurements, blood measurements and delta spectral data confirmed that hemoglobin measurement accuracy is affected by the presence of OHCbl or CNCbl and that the source of interference is from errors in measurement algorithms, and not due to cobalamin induced hemoglobin changes. CONCLUSIONS: Among the 4 co-oximeters tested in this evaluation, GEM Premier 4000 and Rapidpoint 405 analyzer showed minimal impact for hydroxocobalamin concentrations around 0.5 g/l. Cyanocobalamin displayed similar interference effect on co-oximetry measurements as OHCbl. The error detection system in the GEM Premier 4000 appropriately detected and flagged interferences on sample measurements.