Reliability of transcutaneous hemoglobin measurements in an outpatient pediatric clinic

ABSTRACT

Objective

Our study assessed the reliability of a transcutaneous hemoglobin (tcHgb) measurement as compared to a standard capillary hemoglobin (cHgb) measurement in screening for iron deficiency anemia in a single university-based pediatric outpatient clinic.

Methods

Study participants included all pediatric patients requiring a hemoglobin (Hgb) assessment from July 2019 to June 2020. A tcHgb measurement was attempted on all children who received a cHgb measurement. Additional variables evaluated were age, visit type, gender, insurance type, weight, BMI percentile and presence of comorbid conditions.

Results

Of 777 attempts, both cHgb and tcHgb were obtained in 196 children aged 9 months to 21 years. Attempts were most successful in children > 2 years of age due to finger size and ability to remain still for one to two minutes. The mean cHgb was 12.5 ± 1.5 g/dL, mean tcHgb value 13.1 ± 2.1 g/dL, and the mean difference was 0.6 ± 2.1 g/dL (tcHgb-cHgb). An intraclass correlation coefficient was 0.29. There were no differences with regards to age, visit type, gender, insurance type, weight, BMI percentile and presence of comorbid conditions. Bland-Altman analysis displayed a lack of agreement between the tcHgb and cHgb measurements and tcHgb tended to over-estimate Hgb values when the cHgb was low.

Conclusions

The measurement of a transcutaneous Hgb is less invasive for pediatric patients but has significant limitations. Smaller children (probe specifications) and movement limited the ability to obtain a tcHgb measurement in ~75% of children tested. Falsely normal tcHgb values occurred due to overestimation of hemoglobin when compared to the traditional cHgb device. The suboptimal sensitivity of the tcHgb device may cause providers to miss a diagnosis of anemia. Future research should compare both methods of Hgb assessment to the gold standard laboratory-analyzed complete blood count and use a smaller probe for children under 2, once available.

KEYWORDS:

• Pediatrics
• outpatient
• anemia
• hemoglobin
• screening
• health supervision

Funding

This study was fundedwith partial support for this project provided by NIH grant T35-HL007489 to SM. Additionally, the study authors would like to acknowledge the Clinical and Translational Science Institute (CTSI) for their grant support (NIH National Center for Advancing Translational Sciences (NCATS) grant UL1 TR000064).

Disclosure of financial/other conflicts of interest

The authors have no relevant conflicts of interest to disclose. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

None stated.