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

Abstract

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.

Keywords: anemia; blood collection; clinical; field; hemoglobin; variability.

Figure 1.

(A) Differences in mean Hb by arterial (A) and capillary (C) blood source compared with venous (V) or cord blood source as the reference* among infants, children, and adult males (M), females (F), and pregnant women (PW). (B) Differences in mean Hb by single drops of capillary (C) blood source compared with pooled capillary blood source as the reference*, right (R) hand compared with left (L) hand as the standard*, and first venous draw compared with second venous draw as the standard* among children and adult males (M) and females (F).

Figure 2.

(A) Differences in mean Hb of the copper sulfate technique (CST) compared with an automated hematology analyzer (AHA) (reference ) by venous (V) source among infants and children and adult males (M), females (F), and pregnant women (PW). (2B) Differences in mean Hb of the cyanmetHb method (CM) compared with an AHA (reference ) by venous (V) source among infants and children and adult males (M) and females (F). (2C) Differences in mean Hb of the WHO Colour Scale and paper- and color-based methods (PCM) compared with an AHA (reference*) by venous (V) source among infants and children and adult males (M), females (F), and pregnant women (PW).

Figure 3.

(A) Differences in mean Hb of the HemoCue Hb-201+ compared with an automated hematology analyzer (AHA) (reference*) by arterial (A), venous (V), cord, and capillary (C) blood source among infants and children and adult males (M), females (F), and pregnant women (PW). (B) Differences in mean Hb of the HemoCue Hb-301 compared with an AHA (reference ) by arterial (A), venous (V), and capillary (C) blood source among adult males (M) and females (F).

Figure 4.

Differences in mean Hb of the other invasive point-of-care (IPOC) analyzers and clinical blood gas analyzer (CBGA) compared with an automated hematology analyzer (reference*) by venous (V) and capillary (C) blood source among children and adult males (M) and females (F).

Figure 5.

(A) Differences in mean Hb of the noninvasive Masimo Radical-7 analyzer compared with an automated hematology analyzer (AHA) (reference ) by arterial (A) and venous (V) blood source among children and adult males (M) and females (F). (B) Differences in mean Hb of the noninvasive Masimo Pronto-7 analyzer compared with an AHA (reference ) venous (V) blood source children and adult males (M) and females (F). (C) Differences in mean Hb of noninvasive OrSense NBM-200 analyzers (NBM) and other noninvasive point-of-care analyzers (Siemens CO-Oximeter (SO) and Mediscan (MS)) compared with an AHA (reference ) by arterial (A), venous (V), and capillary (C) blood source among infants and adult males (M) and females (F).