Screening for anemia in Red Cross blood donor clinics

Accurate screening for anemia at Red Cross blood donor clinics is essential to maintain a safe national blood supply. Despite the importance of identifying anemia correctly by measurement of hemoglobin or hematocrit (hemoglobin/hematocrit) there is no consensus regarding the efficacy of the current two stage screening method which uses the Readacrit$\sp{\rm tm}$ microhematocrit in conjunction with copper sulfate.^ A cross-sectional study was implemented in which hemoglobin/hematocrit was measured, with the present method and four new devices, on 504 prospective blood donors at a Canadian Red Cross permanent blood donor clinic in London, Canada. Concurrently gathered, venous and capillary blood samples were tested by each device and compared to Coulter S IV$\sp{\rm tm}$ determined venous standard readings. Instrument hemoglobin/hematocrit means were statistically calibrated to the standard ones in order to appraise systematic deviations from the standard. Classification analysis was employed to assess concordance between each instrument and the standard when classifying prospective donors as anemic or non-anemic. This was done both when each instrument was used alone (single stage) and when copper sulfate was used as a preliminary screen (two stage) and simulated over a range of anemia prevalences. The Hemoximeter$\sp{\rm tm}$ and Compur M1000$\sp{\rm tm}$ devices had the highest correlations of hemoglobin measurements with the standard ones for both capillary (n.s.) and venous blood (p $<$.05). Analysis of variance (anova) also showed them to be the most accurate (p $<$.05), as did both single and two stage classification analysis, therefore, they are both recommended. There was a smaller difference between instruments for two stage than for single stage screening; therefore instrument choice is less crucial for the former. The present method was adequate for two stage screening as tested but simulations showed that it would discriminate poorly in populations with a higher prevalence of anemia. The Stat-crit and Readacrit, which measure hematocrit, became less accurate at crucial low hematocrit levels. In light of this finding and the introduction of new, effective and easy to use hemoglobin measuring instruments, the continued use of hematocrit as a surrogate for hemoglobin, is not recommended. ^

SEVERITY OF IRON DEFICIENCY ANEMIA AND ITS RELATIONSHIP TO GROWTH AND MORBIDITY IN A POPULATION OF PRE-SCHOOLERS IN RURAL GUATEMALA (IRON DEFICIENCY, MORBIDITY, GROWTH)

The objectives of this study were to determine the nature of the relationship between severity of iron deficiency anemia, response to iron treatment, respiratory and gastrointestinal illness and weight change. Seventy-five pre-school children from rural Guatemala received daily oral iron therapy for an eleven week period, and were classified into one of three groups having different degrees of iron deficiency anemia. Anthropometric and biochemical data were collected prior and after iron treatment; morbidity data were collected throughout the period of treatment. The outcome variables were percentage weight change, percentage of total days ill with any type of symptom, percentage of total days ill with gastrointestinal symptoms, percentage of total days ill with respiratory symptoms, percentage of total days ill with combination syndrome symptoms. Age, sex and socio-economic status, were independent of any of the independent or outcome variables used. On the other hand, the level of hemoglobin covaried with the height of the children, the smallest children were the most severely anemic. The relationships between hemoglobin levels and weight change, frequency of morbidity (gastrointestinal, respiratory and combination syndrome) and total number of days ill with any symptomatology were investigated. No statistical significance was found in these analyses except when contrasting children with normal hemoglobin levels to iron deficient children, where the findings indicated the normal children experienced more gastrointestinal morbidity. The same relationship were again analyzed but including delta hemoglobin as covariate in the analysis, this latter one was found to be significant at 7% when the percentage of days ill from gastrointestinal morbidity was tested against the hemoglobin groups. The relationship found indicates that, all other covariates accounted for, the percentage of days ill from gastrointestinal morbidity will decrease approximately 1% for each 1% increase in delta of hemoglobin. ^