From the Guidelines
A low RET-HE indicates iron deficiency and necessitates iron supplementation to prevent progression to anemia and improve quality of life. This parameter is a direct assessment of the functional availability of iron to the erythropoietic tissue, as noted in the expert consensus guidelines on intravenous iron uses 1. When RET-HE is low, it suggests that the body's current iron status for erythropoiesis is insufficient, and iron supplementation is typically recommended. The choice of iron supplementation depends on the severity of the deficiency, the presence of absorption issues, and the underlying cause of the deficiency.
Some key points to consider in managing a low RET-HE include:
- Investigating the underlying cause of iron deficiency, such as potential blood loss (gastrointestinal bleeding, heavy menstruation), malabsorption disorders, or dietary insufficiency
- Recommending oral ferrous sulfate 325 mg daily or ferrous gluconate 300 mg daily, taken between meals with vitamin C to enhance absorption, for mild to moderate cases
- Considering intravenous iron formulations like iron sucrose or ferric carboxymaltose for severe cases or those with absorption issues, as outlined in the expert consensus guidelines 1
- Monitoring response to treatment with follow-up testing in 4-6 weeks, including laboratory evaluation of iron parameters such as ferritin, percent transferrin saturation (TSAT), and hemoglobin concentrations, as recommended in the guidelines 1
It is essential to address the underlying cause of iron deficiency and to monitor the response to treatment to prevent clinical complications associated with iron deficiency, even in the absence of anemia, as highlighted in the expert consensus guidelines 1.
From the Research
Interpretation of RET-HE Low
- RET-HE (Reticulocyte Hemoglobin Equivalent) is a parameter used to evaluate iron status and diagnose iron deficiency anemia 2, 3, 4.
- A low RET-HE value indicates iron deficiency or iron deficiency anemia, as it reflects the amount of hemoglobin present in reticulocytes 3, 4.
- Studies have shown that RET-HE is a useful marker for diagnosing iron deficiency and iron deficiency anemia, with a cutoff value of 25.4 pg or below predicting iron deficiency diagnosis with 90.4% sensitivity and 49.1% specificity 3.
- RET-HE is also useful for monitoring response to iron therapy, as it increases within days of initiation of iron therapy 4.
- In cases of mixed anemia (vitamin B12 deficiency and iron deficiency anemia), RET-HE can be used to differentiate between the two conditions, along with other reticulocyte parameters such as MCVr (Reticulocyte mean corpuscular volume) and CHCMr (Corpuscular mean hemoglobin concentration of reticulocyte) 5.
Diagnostic Criteria
- A RET-HE value of 28 pg or below is considered low, indicating iron deficiency or iron deficiency anemia 2.
- A RET-HE value of 25.4 pg or below predicts iron deficiency diagnosis with 90.4% sensitivity and 49.1% specificity 3.
- The diagnosis of iron deficiency anemia should be based on a combination of clinical evaluation, laboratory tests, and reticulocyte parameters, including RET-HE 6.
Clinical Implications
- A low RET-HE value may indicate the need for iron supplementation or other treatments to address iron deficiency or iron deficiency anemia 2, 3, 4.
- Monitoring RET-HE values can help assess the effectiveness of iron therapy and adjust treatment as needed 4.
- RET-HE can be used as a simple and affordable tool for screening and diagnosing iron deficiency and iron deficiency anemia, particularly in populations with limited access to other diagnostic tests 2, 4.