Influence of measurement principle on total hemoglobin value

Abstract

Background: Total hemoglobin (tHb) measurement is indispensable for determining the patient's condition (hemorrhagic vs. ischemic) and need for blood transfusion. Conductivity-and absorbance-based measurement methods are used for blood gas analysis of tHb. For conductivity-based measurement, tHb is calculated after converting blood conductivity into a hematocrit value, whereas absorbance measurement is based on light absorbance after red blood cell hemolysis. Due to changes in plasma electrolytes and hemolysis, there is a possibility that conductivity-and absorbance-based measurement methods may cause a difference in tHb. Methods: In this study, test samples with controlled electrolyte changes and hemolysis were created by adding sodium chloride, distilled water or hemolytic blood to blood samples collected from healthy volunteers, and tHb values were compared between both methods. Results: Conductivity-based measurement revealed reduced tHb value (from 15.49 to 13.05 g/dl) following the addition of 10% sodium chloride, which was also reduced by the addition of hemolysate. Conversely, the addition of distilled water significantly increased tHb value than the expected value. In the absorbance method, there was no significant change in tHb value due to electrolyte change or hemolysis. Conclusions: We have to recognize unexpected conductivity changes occur at all times when tHb is measured via conductivity-and absorbance-based measurement methods. The absorbance method should be used when measuring tHb in patients with expected blood conductivity changes. However, when using this method, the added contribution of hemoglobin from hemolytic erythrocytes lacking oxygen carrying capacity must be considered. We recognize that discrepancy can occur between conductivity-and absorbance-based measurement methods when tHb is measured.

A retrospective study: screening failure analysis of 1,058 healthy volunteers in phase I clinical trials

“…For example, recent diets, work and rest time, activity intensity, and the stress state of volunteers may affect the results of liver function, kidney function, blood glucose, blood lipid, electrolyte, and muscle enzyme tests (18)(19)(20)(21). In addition, hemolysis of samples may affect lactate dehydrogenase, aspartate transaminase, and kalemia test (22,23). Secondly, problems such as different testing equipment and reagents in different regions and different races will lead to different reference ranges for laboratory tests (22,23).…”

“…In addition, hemolysis of samples may affect lactate dehydrogenase, aspartate transaminase, and kalemia test (22,23). Secondly, problems such as different testing equipment and reagents in different regions and different races will lead to different reference ranges for laboratory tests (22,23). As a result, it is difficult for researchers in different research centers to define the scope of no clinical significance (NCS).…”

Monitoring methaemoglobinaemia in birds using 5 μL of whole blood

“…Closer temporal alignment of data collection or replication of Cera-Check HbFe 2+ data using an average of multiple readings, may assist to reduce outliers. Discrepancies between absorbance-based measurements of haemoglobins and those using biosensors reliant on different analytical principles may also occur due to haemolysis [49], or if the concentration of reticulocytes varies between individuals [50], neither of which we sought to qualify. Unlike laser flow cytometry used in automatic haematology analysers, we obtained no information about the size and shape of cells [51], meaning that it is also possible that variation in several erythrocyte indices, such as mean crepuscular volume (MCV) could also have accounted for variations in absorbance data relative to total HbFe 2+ concentrations [52].…”

Current and Emerging Microfluidic-Based Integrated Solutions for Free Hemoglobin and Hemolysis Detection and Measurement

“…The blood sample passes through a fluidic channel where its conductance is measured by measuring the potential difference between the two electrodes placed across the fluidic channel. After correcting the variable conductivity of plasma through the concentration measurement of sodium and potassium in the sample, the hematocrit value is estimated according to the characteristic inverse relationship between the number and size of RBCs and their electrical conductance in the blood specimen. , Corrections need to be applied using the relative conductivity of plasma and its temperature before Hgb concentration is then calculated. The Epoc (Siemens Medical Solutions Diagnostics, Zurich, Switzerland, ), ABL77 Series Blood Gas and Electrolyte Analyzer, and iSTAT (Abbott, Princeton, NJ) devices use this technique for hematocrit level measurement.…”