Evaluation of the Hb-Quick (R): A portable hemoglobinometer

Objective. The Hb-Quick(R) is a new portable hemoglobinometer that uses dis posable cuvettes to measure the total hemoglobin concentration of capillary , venous, or arterial blood. Therefore, the objectives of this study were 1 ) to evaluate the performance of this compact, battery-powered hemoglobinom eter by assessing its precision, accuracy, and linearity, 2) to determine w hether its measurements suffer from interference by hemolysis, bilirubin, f etal hemoglobin, or hemodilution, and 3) to establish whether it can easily be used by clinical personnel with little or no laboratory training. Metho ds. The precision of the test instrument was assessed by making repeated me asurements on blood samples. Its accuracy and linearity were evaluated by c omparing its measurements with the internationally accepted cyanmethemoglob in method. Samples of whole blood with and without bilirubin, fetal hemoglo bin, hemolysis, and hemodilution were also analyzed to determine if any int erference occurred when these disturbances were present, and it was placed in physicians' offices to evaluate its use by non-laboratory personnel. Res ults. Repeated measurements on blood samples with a wide range of hemoglobi n concentrations were consistent with the precision specification (0.25 g/d l). The bias of the new hemoglobinometer was calculated as the mean differe nce between its readings and measurements with the cyanmethemoglobin method , and its accuracy as the standard deviation of the differences between the two methods. As assessed in this manner, the new hemoglobinometer had a bi as of -0.04 g/dl and an accuracy of 0.40 g/dl. The linearity was checked ov er a hemoglobin concentration range from 0 to nearly 30 g/dl. There was a h ighly significant linear relationship between its readings and measurements with the cyanmethemoglobin method (slope = 0.997, y-intercept = 0.005, r = 0.999). Complete hemolysis of the sample increased the readings on average by only 0.22 g/dl. Bilirubin (17.5 mg/dl) increased the reading by an aver age of 0.29 g/dl, and fetal hemoglobin (76.5% HbF) reduced the readings by an average of only 0.035 g/dl. Diluting blood samples with saline also did not appreciably affect its accuracy. Conclusions. The new hemoglobinometer is fast and easy to operate. No sample preparation or pipetting is required . To operate the instrument, the user simply allows a drop of blood to fill the disposable cuvette by capillary action and inserts the cuvette into th e instrument. The instrument analyzes the 10 mu l sample and displays the r esults in less than 10 seconds. The interference caused by hemolysis, hemod ilution with saline, fetal hemoglobin, and bilirubin were too small to be o f any clinical importance. Tests in physician's offices indicated that clin ical personnel with little or no formal laboratory training could successfu lly use this device. The observed precision, accuracy, linearity, and freed om from interference indicate that this hemoglobinometer is suitable for ne ar-patient testing in a wide range of clinical settings including physician s' offices.