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Am J Perinatol 2025; 42(07): 834-841
DOI: 10.1055/a-2419-9404
SMFM Fellowship Series Article

Utility of Reticulocyte Hemoglobin Equivalent in Screening for Iron Deficiency in Pregnancy

Lylach Haizler-Cohen 
1   Department of Obstetrics and Gynecology, MedStar Washington Hospital Center, Washington, District of Columbia
,
Haleema Saeed
1   Department of Obstetrics and Gynecology, MedStar Washington Hospital Center, Washington, District of Columbia
,
Valencia Quiett
2   Bloodless Medicine and Surgery Program, MedStar Georgetown University Hospital, Washington, District of Columbia
,
Gurpinder Kaur
1   Department of Obstetrics and Gynecology, MedStar Washington Hospital Center, Washington, District of Columbia
,
Eshetu A. Tefera
3   Department of Biostatistics, MedStar Health Research Institute, Hyattsville, Maryland
,
Samrawit Gizaw
3   Department of Biostatistics, MedStar Health Research Institute, Hyattsville, Maryland
,
Richard Verstraete
2   Bloodless Medicine and Surgery Program, MedStar Georgetown University Hospital, Washington, District of Columbia
,
Michael Auerbach
4   Department of Medicine, Georgetown University School of Medicine, Washington, District of Columbia
,
Nicholas Hazen
5   Department of Obstetrics and Gynecology, MedStar Georgetown University Hospital, Washington, District of Columbia
› Author Affiliations Funding The Medstar Health Graduate Medical Education helped support the laboratory testing and statistical analysis for this study.
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Abstract

Objective

Ferritin, commonly used for diagnosing iron deficiency (ID) in pregnancy, is limited by high cost and false elevations during inflammation. Reticulocyte hemoglobin equivalent (Ret-He), an alternative marker for ID, is unaffected by inflammation and analyzed on the same collection tube as the standard complete blood count (CBC). We aimed to determine the accuracy of Ret-He in detecting ID in pregnancy compared to ferritin in a U.S. cohort.

Study Design

This prospective cohort study enrolled 200 pregnant participants, recruited in any trimester if a CBC was drawn as part of routine prenatal care. For those who agreed to participate, Ret-He and ferritin were collected concurrently with the CBC. ID was defined as ferritin level below 30 ng/mL. Patients were classified into three groups based on hemoglobin and ferritin results to determine the severity of ID: no ID, ID alone, and ID anemia (IDA). Four participants with anemia but normal ferritin were excluded. Receiver operating curve analysis, including the area under the curve (AUC), was performed to assess the accuracy of Ret-He in detecting ID. A one-way ANOVA (analysis of variance) with post-hoc analysis was used to compare differences in Ret-He between the three groups of ID severity.

Results

The prevalence of ID in our cohort was 82% (161/196). The AUC for Ret-He was 0.65 (95% confidence interval: 0.55–0.75), indicating suboptimal discrimination between patients with and without ID. Ret-He was significantly different among the three groups (p < 0.001). In post-hoc analysis, Ret-He was significantly lower in the IDA group compared to the ID group (p < 0.001) but there was only a trend of lower Ret-He in the ID group compared to the non-ID group (p = 0.38).

Conclusion

Ret-He has low accuracy in diagnosing ID in pregnancy. It may be useful in detecting severe ID resulting in anemia but not a mild iron-deficient state resulting in ID only.

Key Points

  • The prevalence of ID in our cohort was 82%.

  • Ret-He has low accuracy in diagnosing ID in pregnancy.

  • Ferritin is preferable when readily available.

Keywords

anemia - ferritin - iron deficiency - pregnancy - reticulocyte - reticulocyte hemoglobin equivalent

Note

The findings of this study were presented at the 44th Annual Pregnancy Meeting by the Society for Maternal Fetal Medicine, National Harbor, MD, February 10 to 14, 2024.




Publication History

Received: 25 May 2024

Accepted: 20 September 2024

Accepted Manuscript online:
24 September 2024

Article published online:
10 October 2024

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