Accuracy of noninvasive total haemoglobin measurement for detecting anaemia in infants: a cross-sectional study in a well-child care clinic, Khon Kaen, Thailand.

OBJECTIVE

Infants are at a high risk of developing anaemia, which can arise from various causes, including inappropriate feeding practices. However, few infants attend anaemia screening programmes due to poor cooperation and being time-consuming. This study evaluated the accuracy of noninvasive total haemoglobin (Hb) spot-check monitoring as part of anaemia screening in healthy infants, compared with the conventional laboratory method.

DESIGN

A cross-sectional study was conducted using a consecutive sampling technique.

SETTING

The study was carried out at the Well-Child Clinic, Khon Kaen University, Thailand.

PARTICIPANTS

Healthy, full-term infants aged 6-12 months who were scheduled for vaccination. Spectrophotometric haemoglobin (SpHb) was measured using Masimo Rad-67 with Rainbow DCI-mini Sensor. These values were compared with conventional laboratory analysis (HbLab) performed on the same day.

PRIMARY AND SECONDARY OUTCOME

Differences between Hb values using the two methods were analysed using the Bland-Altman method. Sensitivity, specificity and positive and negative predictive values (PPV and NPV) for detecting anaemia were determined. Anaemia was defined as HbLab of <11.0 g/dL.

RESULTS

A total of 104 infants, with a median age of 9.6 (IQR 9.3, 10.9) months, were included. The prevalence of anaemia, defined by HbLab, was 38.46%. The mean SpHb was 12.20±1.10 g/dL, while the mean HbLab was 11.19±1.21 g/dL. A moderate positive correlation was observed (=0.575, p<0.001). Bland-Altman analysis of SpHb vs HbLab showed an estimated bias of 1.007 g/dL with a 95% limit of agreement ranging from -1.091 to 3.104 g/dL. The mean bias was 1.635 g/dL (-0.617 to 3.887) in the anaemic group and 0.614 g/dL (-0.964 to 2.192) in the nonanaemic group. Using the SpHb cut-off point of <13.0 g/dL, the sensitivity and specificity of SpHb to detect anaemia were 95.0% and 35.9%, with PPV and NPV of 48.1% and 92.0%, respectively.

CONCLUSION

A noninvasive tool for measuring Hb, with moderate sensitivity and NPV, may provide utility for initial screening to reduce unnecessary venipuncture in infants. However, its limited specificity and PPV necessitate confirmatory testing through conventional laboratory methods for accurate diagnosis. Depending on the context and available resources, it has potential to complement existing diagnostic processes, particularly in settings where rapid and noninvasive screening is prioritised.

TRIAL REGISTRATION NUMBER

Thai Clinical Trials Registry (TCTR20210816002).