Assessing Accuracy and Precision of Hemoglobin Determination in Venous, Capillary Pool, and Single-Drop Capillary Blood Specimens Using three Different HemoCue® Hb Models: The Multicountry Hemoglobin Measurement (HEME) Study.

BACKGROUND: Anemia prevalence estimates reported in population surveys can vary based on the blood specimen source (capillary or venous) and analytic device (hematology autoanalyzers or portable hemoglobinometers) used for hemoglobin (Hb) determination. OBJECTIVES: This study aimed to compare accuracy and precision of Hb measurement in three blood specimen types on three models of hemoglobinometers against the results from venous blood from the same individuals measured on automated analyzers (AAs). METHODS: This multisite (Cambodia, Ethiopia, Guatemala, Lebanon, Nigeria, and Tanzania) study assessed Hb measurements in paired venous and capillary blood specimens from apparently healthy women (aged 15-49 y) and children (aged 12-59 mo) using three HemoCue® Hb models (201+, 301, and 801). Measurements were compared against reference values: venous blood in hematology AA and adjusted via regression calibration or mean difference in HemoCue® Hb. Venous, capillary pool, and single-drop capillary blood specimens were assessed for accuracy and precision. RESULTS: Venous blood measured using HemoCue® Hb 301 exhibited a positive mean error, whereas responses in HemoCue® Hb 201+ and 801 were nondirectional compared with the reference. Adjustment with the reference harmonized mean errors for all devices across study sites to <1.0 g/L using venous blood. Precision was highest for venous blood (±5-16 g/L) in all sites, lowest for single-drop capillary (±9-37 g/L), and intermediate (±9-28 g/L) for capillary pool blood specimen. Imprecision differed across sites, especially with both capillary blood specimens, suggesting different levels of personnel skills. CONCLUSIONS: Findings suggest that venous blood is needed for accurate and precise Hb determination. Single-drop capillary blood use should be discouraged owing to high measurement variability. Further research should evaluate the viability and reliability of capillary pool blood for this purpose. Accuracy of HemoCue® Hb devices can be improved via standardization against results from venous blood assessed using AA.

Downregulation and altered function of natural killer cells in hepatitis B virus patients treated with entecavir.

The aim of the present study was to investigate the natural killer (NK) cell phenotype and function in chronic hepatitis B virus (HBV) patients and to study the effects of entecavir therapy (10 mg/day, p.o.) on these responses. Peripheral blood NK cells were collected from 18 chronic HBV patients and 14 healthy controls. The effect of entecavir therapy on the phenotype and function of NK cells in chronic HBV patients was characterized by flow cytometry analysis. Concentrations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), HBV viral loads in both groups and potential associations between the frequency of peripheral NK cell subsets and clinical measures were determined. There was a significant reduction in the number of CD3(-)CD56(+) NK cells in chronic HBV patients compared with healthy controls. Furthermore, there were significant increases in the percentage of CD3(-)CD56(+)NKG2D(+) and CD3(-)CD56(+)NKP30(+) NK activating receptors in chronic HBV patients compared with healthy individuals, who exhibited downregulated expression following entecavir treatment. Spearman's correlation analysis revealed that there was a significant positive correlation between the percentage of NKG2D(+) and NKP30(+) NK cells and serum ALT levels. Characterization of NK cell degranulation indicated that the frequency of CD107a(+) NK cells in HBV patients (in response to K562 stimulation) was significantly greater than in healthy controls but decreased following entecavir treatment. Entecavir treatment of hepatitis B e antigen-positive chronic HBV-infected patients not only led to a reduction in HBV DNA loads and normalization of ALT and AST levels, but also resulted in the recovery of NK cell-mediated immunity.