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To assess the effect of hemolysis on serum retinol concentrations determined by direct fluorometry, we assayed 196 blood samples from children 6-72-mo of age with various grades of hemolysis for serum retinol by both fluorescence and HPLC. Mean serum retinol concentrations determined by HPLC did not differ significantly according to hemolysis grade; however, fluorometric values did. Additionally, serum retinol concentrations obtained from HPLC and those obtained from direct fluorometry were significantly different in samples with severe hemolysis. Multivariate-regression analysis showed that hemolysis grade was a significant predictor of the difference in mean serum retinol values determined by the two methods. Although severe hemolysis interfered with determinations of serum retinol by direct fluorometry, this method is still a viable choice for field studies of vitamin A status.

Background: Studies in developing countries have shown that children with measles have low serum retinol concentrations and that lower retinol levels are associated with measles-related mortality. Vitamin A therapy has been shown to reduce mortality among African children with acute measles., Objectives: To determine whether serum retinol concentration is low among children with measles in the United States and to determine whether retinol concentration is associated with illness severity., Setting: Pediatric referral hospital and clinic in Milwaukee, WI, during the measles outbreak of 1989-1990., Patients: One hundred fourteen patients < or = 5 years of age evaluated for serologically confirmed measles with serum obtained within 5 days following rash onset., Methods: Serum retinol concentration was determined by high-performance liquid chromatography. Clinical data were collected by hospital record review. A modified Pediatric Risk of Mortality (PRISM) score was used to assess physiologic instability as a measure of illness severity., Results: Retinol concentrations ranged from 0.25 to 1.18 mumol/L (median 0.58 mumol/L); 82 (72%) patients had low retinol concentration (< or = 0.70 mumol/L). Median retinol concentrations were lower among hospitalized patients (0.56 vs 0.70, P = .006) and patients with pneumonia (0.52 vs 0.64, P = .02) but higher among children with otitis media (0.63 vs 0.54, P = .01). Higher modified PRISM scores, reflecting greater physiologic instability, were associated with lower retinol concentration (beta coefficient -.0147, P = .025). In multivariate analysis, higher modified PRISM scores were associated with lower retinol concentration (beta coefficient -.0144, P = .025) even after controlling for hospitalization, presence of complications, race, age, receipt of Aid to Families With Dependent Children, gender, and interval from rash onset until serum was collected., Conclusions: Among these children with measles in an urban United States community, retinol concentrations were depressed, and the degree of depression was associated with illness severity. Vitamin A therapy should be considered for children with measles in the United States who require hospitalization.

Recent studies show that vitamin A levels decrease during measles and that vitamin A therapy can improve measles outcome in children in the developing world. Vitamin A levels of children with measles have not been studied in developed countries. We therefore measured vitamin A levels in 89 children with measles younger than 2 years and in a reference group in New York City, NY. Vitamin A levels in children with measles ranged from 0.42 to 3.0 mumol/L; 20 (22%) were low. Children with low levels were more likely to have fever at a temperature of 40 degrees C or higher (68% vs 44%), to have fever for 7 days or more (54% vs 23%), and to be hospitalized (55% vs 30%). Children with low vitamin A levels had lower measles-specific antibody levels. No child in the reference group had a low vitamin A level. Our data show that many children younger than 2 years in New York City have low vitamin A levels when ill with measles, and that such children seem to have lower measles-specific antibody levels and increased morbidity. Clinicians may wish to consider vitamin A therapy for children younger than 2 years with severe measles. Additional studies of vitamin A in measles and other infectious diseases, and in vaccine efficacy trials, should be done.