Zinc protoporphyrin (ZPP) may be a simple screening test for iron deficiency (ID) and iron deficiency anemia in infants and toddlers, according to a study published online Feb. 18 in JAMA Pediatrics. Despite recommendations for universal screening for ID in all 1-year-olds, diagnosis remains a challenge for primary care clinicians because of the lack of an ideal screening test. The authors say that using hemoglobin as a first screen misses large groups of infants with ID without anemia. The 2010 American Academy of Pediatrics recommendations call for screening for ID with ferritin and C-reactive protein or serum transferrin receptor-1 saturation and reticulocyte hemoglobin level, which are not routinely available to practitioners. “The [ZPP] test is cheap and can be done on capillary blood at the point of service,” writes Robert Baker, M.D., Ph.D., from Children’s Hospital of Buffalo in N.Y., in an accompanying editorial. “However, there are a number of factors that affect ZPP levels including lead poisoning, myelodysplasia, chronic inflammation, and altered iron metabolism.” The JAMA Pediatrics study retrospectively reviewed longitudinal electronic medical records data collected at a primary care center (2002 to 2010) among 2,612 kids (between the ages of 8 months and 18 months) seen for routine […]
Zinc protoporphyrin (ZPP) may be a simple screening test for iron deficiency (ID) and iron deficiency anemia in infants and toddlers, according to a study published online Feb. 18 in JAMA Pediatrics. Despite recommendations for universal screening for ID in all 1-year-olds, diagnosis remains a challenge for primary care clinicians because of the lack of an ideal screening test.
The authors say that using hemoglobin as a first screen misses large groups of infants with ID without anemia. The 2010 American Academy of Pediatrics recommendations call for screening for ID with ferritin and C-reactive protein or serum transferrin receptor-1 saturation and reticulocyte hemoglobin level, which are not routinely available to practitioners.
“The [ZPP] test is cheap and can be done on capillary blood at the point of service,” writes Robert Baker, M.D., Ph.D., from Children’s Hospital of Buffalo in N.Y., in an accompanying editorial. “However, there are a number of factors that affect ZPP levels including lead poisoning, myelodysplasia, chronic inflammation, and altered iron metabolism.”
The JAMA Pediatrics study retrospectively reviewed longitudinal electronic medical records data collected at a primary care center (2002 to 2010) among 2,612 kids (between the ages of 8 months and 18 months) seen for routine care, all with baseline and follow-up screening results for complete blood cell count, lead, and ZPP. ZPP had been previously analyzed to screen for lead toxicity. ZPP was measured using hematofluorometry with abnormal levels defined as greater than or equal to 35 μg/dL.
At baseline 48 percent of children had an abnormal ZPP level, with 84 percent of these children not testing as anemic. Abnormal ZPP was not significantly associated with race or ethnicity. Among those with abnormal ZPP, 18 percent were prescribed iron. At follow-up, iron prescription was significantly associated with a reduction in abnormal ZPP results among those who were anemic and was tied to a substantial, but not statistically significant, trend to improvement in those prescribed iron with low-normal hemoglobin.
