Bedside diagnostic blood testing. Its accuracy, rapidity, and utility in blood conservation

--Bedside diagnostic testing utilizing microchemistry instruments potentially offers physicians the opportunity to evaluate urgent blood test results rapidly and reliably using only drops (250 microL) of whole blood. The use of microchemistry technology may also represent an essential component of a blood conservation program in acutely ill patients. We tested the hypothesis that a microchemistry instrument would have important advantages in the intensive care unit, including rapid turnaround time, decreased iatrogenic blood loss, and the provision of accurate analyte results.

--One-year prospective, random-sample comparative study.

--A tertiary, acute care, 1000-bed university teaching hospital and a 450-bed university-affiliated community hospital.

--Blood samples from 850 patients were analyzed.

--There were strong correlations (for pH, R2 = .97; PCO2, R2 = .97; PO2, R2 = .99; sodium, R2 = .83; potassium, R2 = .94; chloride, R2 = .90; glucose, R2 = .98; and hematocrit, R2 = .92) when paired samples were analyzed simultaneously in the laboratory comparing the microchemistry instrument and currently accepted clinical laboratory instruments. There were significant correlations (for pH, R2 = .91; PCO2, R2 = .94; PO2, R2 = .97; sodium, R2 = .91; potassium, R2 = .86; chloride, R2 = .91; ionized calcium, R2 = .82; glucose, R2 = .96; and hematocrit, R2 = .75) but increased variability occurred in some analyte results when samples were first analyzed in the intensive care unit (using the microchemistry instrument) and then transported to the laboratory in the routine fashion for "stat" determinations.

--The multichannel microchemistry instrument provided accurate analyte determinations when compared with accepted clinical laboratory instruments. Significant savings of time and blood were also realized by the use of a microchemistry instrument in the intensive care unit. Bedside microchemistry may provide clinically important advantages in emergency departments, operating rooms, and neonatal, pediatric, coronary, adult medical and surgical, trauma, and burn intensive care units.