Evaluation of two-step haemoglobin screening with HemoCue for blood donor qualification in mobile collection sites

Comparison of the accuracy of capillary hemoglobin estimation and venous hemoglobin estimation by two models of HemoCue against automated cell counter hemoglobin measurement

BACKGROUND:

HemoCue point of care devices has been extensively used in screening for anemia in blood banking. HemoCue can estimate hemoglobin (Hb) both from venous as well as capillary blood. However, the suitability of HemoCue Hb estimation in donor selection is unclear.

AIMS:

The aims of this study were to evaluate variance of difference in Hb measurement in capillary HemoCue estimation as compared to venous HemoCue estimation from automated cell counter and to assess accuracy of two different HemoCue models (201 and 301) against automated cell counter Hb measurements in both capillary as well as venous blood.

MATERIALS AND METHODS:

HemoCue 201 and 301 were evaluated by a comparison of methods study against Sysmex XP-100 three-part analyzer at a blood bank of a tertiary care hospital in Uttarakhand, India, in 2017. Assessment for anemia of 115 donors was done initially by capillary Hb by a convenience sampling to 2 instruments from 2 different models of HemoCue (total of 4 instruments). Venous blood collected was analyzed by Sysmex XP-100 and all HemoCue analyzers.

RESULTS:

For capillary method, bias ranged from −0.97 to −0.37 g/dL, upper limit of agreement (LOA) ranged from 0.72 to −1.06 g/dL, and lower LOA ranged from −2.65 to −1.79 g/dL. For venous method, bias ranged from −0.03 to −0.24 g/dL, the upper LOA ranged from 0.81 to −1.07 g/dL, and lower LOA ranged from −1.04 to −0.57 g/dL. Thus, capillary HemoCue estimation exhibited greater bias as well as wider LOA. Variance of the differences from automated counter was significantly lower for venous HemoCue comparison compared to capillary HemoCue estimation (P < 0.001 for each instrument).

CONCLUSION:

Errors in capillary sampling of blood show the extent to which preanalytical errors can influence results in point-of-care devices. We suggest augmentation of any blood bank-based Hb screening process based just on capillary sampling to be augmented by a properly selected venous sampling to reduce deferral for a false-positive screen of anemia.

Venous sample is superior to repeated skin-prick testing in blood donor haemoglobin second-line screening

BACKGROUND

Blood donor haemoglobin concentration (Hb) is commonly measured from a skin-prick sample. However, the skin-prick sample is prone to preanalytical error and variation, which may lead to false deferrals due to low Hb.

STUDY DESIGN AND METHODS

We assessed the efficacy of two second-line screening models for the evaluation of blood donors failing the initial skin-prick test. In the venous model (n = 305), Hb was measured from a venous sample at the donation site. In the skin-prick model (n = 331), two additional skin-prick samples were measured. All on-site Hb measurements were performed with HemoCue Hb201+ (HemoCue AB) point-of-care (POC) device. Hb in the venous samples was later also determined with a hematology analyzer (Sysmex XN, Sysmex Co.) to obtain the donor's correct Hb. A questionnaire evaluated Blood Service nurses' preferences regarding Hb assessment.

RESULTS

Significantly less donors were deferred from donation with venous model (40%) than with skin-prick model (51%; chi-square test P = 0·004). Only two donors (0·7%) were incorrectly accepted in the venous model. Further, Blood Service nurses preferred venous model over skin-prick model. After the study, the venous model was implemented nationwide, and in the first two months after implementation, the deferral rate due to low Hb decreased from 2·7% to 1·9%.

CONCLUSION

A venous sample for blood donor Hb second-line screening significantly decreased low Hb deferrals compared to repeated skin-prick testing without compromising donor safety. Valuable donations can be recovered by implementing a practical second-line screening model based on venous sampling.

Anaemia in school-aged children in an Australian Indigenous community

OBJECTIVE

Indigenous Australians have poorer health outcomes compared to the non-Indigenous population. Malnutrition, and subsequently iron-deficiency anaemia, impairs childhood development. The aim of this study was to identify the prevalence of anaemia in school-aged children of an Australian Indigenous community and evaluate the effectiveness of treatment.

DESIGN

A retrospective cohort study.

SETTING

A Northern Territory Indigenous community.

PARTICIPANTS

Two hundred and one school-age students (5-15 years old) undergoing annual school screening.

MAIN OUTCOME MEASURES

Presence of anaemia. Anaemic and non-anaemic students were compared to determine any differences in age, gender, BMI and past history of anaemia. The response to treatment was analysed using initial and repeat haemoglobin results.

RESULTS

Altogether, 201 students were screened with 105 (52%) classified as anaemic. No significant association was found between anaemic students and age, gender, BMI or prior history of anaemia. After treatment, the mean rise in haemoglobin was 13% (95% CI 11-15) at the 4-week interval. Age (P = 0.17), gender (P = 0.53) and weight (P = 0.14) were not significantly associated with treatment efficacy. Only 11 students (17%) were still anaemic after treatment.

DISCUSSION

Anaemia in Indigenous Australian school-aged children is a major public health issue. The prevalence of anaemia in this population is 52% and many times higher than that of the general Australian population. As per current guidelines, the recommended treatment is effective in over 80% at the 4-week interval. Community wide interventions are required to combat this alarming issue.