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Failure of hematocrit to detect iron deficiency in infants
1Navajo Nation Health Foundation, Sage Memorial Hospital, Ganado, Arizona 86505, USA.
Insights
Hematocrit screening for iron deficiency in infants misses many cases. Serum ferritin is a more sensitive indicator in low-income populations, highlighting the need for improved diagnostic methods.
Area of Science:
- Pediatric Nutrition
- Public Health
- Hematology
Background:
- Infants from low-income families face a threefold higher risk of iron deficiency.
- Iron deficiency can lead to psychomotor deficits, particularly when it causes anemia.
- Current screening at 9-12 months using hematocrit may fail to detect iron deficiency in non-anemic infants.
Purpose of the Study:
- To evaluate the effectiveness of hematocrit as a screening tool for iron deficiency in high-risk infants.
- To compare hematocrit measurements with serum ferritin levels in detecting iron deficiency.
Main Methods:
- A study involving 321 infants aged 9-18 months from low-income families in Houston, Texas.
- Capillary blood samples were collected for hematocrit (Hct) testing, with Hct < or = 33% as the standard criterion.
- Serum ferritin levels were measured concurrently to assess iron status.
Main Results:
- Only 1.9% of infants were anemic, with no cases attributed to iron deficiency.
- A significant 15.9% of infants were identified as iron deficient based on low serum ferritin (<10 micrograms/L), yet none were anemic.
- Hematocrit and serum ferritin levels showed no statistical correlation.
Conclusions:
- Hematocrit is an inadequate screening test for iron deficiency in this infant population.
- While iron deficiency was mild, a more sensitive screening method is necessary for early detection in high-risk groups.
- Further research is required to establish the prevalence of iron deficiency in similar high-risk populations.
Background:
Infants of low-income families have three times the risk of iron deficiency as those of families above the poverty level. Psychomotor deficits have been associated with iron deficiency once it produces anemia. High-risk infants are usually screened for iron deficiency between 9 and 12 months of age with a hematocrit measurement. This type of screening may miss iron-deficient infants who are not yet anemic.
Methods:
In the well-child clinics for low-income families in Houston, Texas, a hematocrit (Hct) < or = 33% is the standard screening criterion for iron deficiency. Three hundred twenty-one infants between the ages of 9 and 18 months had capillary blood drawn for Hct testing. Serum ferritin levels were simultaneously measured.
Results:
Six (1.9%) of the 321 infants were anemic, but none because of iron deficiency. Fifty-one infants (15.9%) were iron deficient (ferritin <10 micrograms/L), none of whom were anemic. Hematocrit and ferritin levels did not correlate statistically.
Conclusions:
The Hct is not an adequate screening test for iron deficiency in this population of infants. Although this population is usually considered high-risk, iron deficiency was mild. Selective screening of high-risk infants in this population may be appropriate, but a more sensitive screening test is required. Further studies are needed to determine the prevalences of iron deficiency in this and other high-risk populations.
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