Comparison of haemoglobin estimates using direct & indirect cyanmethaemoglobin methods

Validation of Point of Care Hemoglobin Estimation Among Pregnant Women Using Digital Hemoglobinometers (HemoCue 301 and HemoCue 201+) as Compared with Auto-Analyzer

Accurate and reliable point of care tests (POCTs) for hemoglobin estimation is essential for early diagnosis and management of anemia. This study was aimed to assess the reliability and validity of two versions of digital hemoglobinometer (HemoCue 201+ and HemoCue 301) compared to the gold standard Sysmex autoanalyzer for hemoglobin estimation. Pregnant women attending antenatal clinics of Primary Health Centre and a Sub Divisional Hospital in Haryana, India, were recruited. After obtaining consent, capillary blood samples were collected and tested for hemoglobin levels with digital hemoglobinometers (HemoCue 201+ and HemoCue 301). Among same pregnant women venous blood was collected and hemoglobin levels were estimated using autoanalyzer. Validity and reliability of POCTs compared to Sysmex autoanalyzer were reported. Of the 102 pregnant women included in the study, 44 (43%) were primigravida, with mean (SD) age of 23.3 (3.4) years. The mean (SD) of difference in hemoglobin levels using HemoCue 201+ was - 0.53 (1.01) and using HemoCue 301 was - 0.25 (0.85) g/dL as compared to auto-analyzer. Lin's concordance coefficient was 0.80 for HemoCue 201+ and 0.85 for HemoCue 301. Weighted Cohen's Kappa indicated moderate degree of agreement with the gold standard. Sensitivity (HemoCue 201+: 93%; HemoCue 301: 90%) and specificity (HemoCue 201: 76% HemoCue 301: 80%) for detecting anemia was similar for both the POCT devices. The digital hemoglobinometers used in the study had moderate degree of agreement and concordance with the autoanalyzer for hemoglobin estimation. HemoCue 301 had higher validity as compared to HemoCue 201+.

Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings

This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of ±7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0  g/L), WHO Colour Scale (0.5-10.0  g/L), paper-based devices (5.0-7.0  g/L), HemoCue® Hb-201 (1.0-16.0  g/L) and Hb-301 (0.5-6.0  g/L), and Masimo Pronto® (0.3-14.0  g/L) overestimated concentrations; (2) Masimo Radical®-7 both under- and overestimated concentrations (0.3-104.0  g/L); and (3) other methods underestimated concentrations (2.0-16.0  g/L). Most mean concentration comparisons varied less than ±7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.