Evaluation of Hemoglobin Measurement Tools for Child Anemia Screening in Rwanda

The Hb values of 132 children, between 6 and 59 months of age will be obtained, using three different Hb assessment methods during the same assessment visit for comparison with the standard reference hematology analyzer(Sysmex KN21) results.

The purpose of the research is: 1) To evaluate the accuracy of the noninvasive Masmio Pronto® device with DCI-mini sensor in measuring Hb when compared to measuring Hb using the standard reference hematology analyzer, and 2) To evaluate the accuracy of both the HemoCue® Hb 201+ gravity and wicking methodologies of capillary blood collection against the standard reference hematology analyzer.

To validate and determine the accuracy of the Pronto® with DCI-mini™ sensor, the 132 Pronto® Hb values will be compared to the Hb values obtained by the standard reference hematology analyzer to determine if the overall average difference between measurements does not exceed 1.0g/dL.

To validate and determine the accuracy of each of the two HemoCue® 201+ blood collection methods, 50% of the children will have their Hb measured using the wicking method and 50% will have their Hb measured using the gravity method. The Hb values obtained by the two different HemoCue® 201+ blood collection methods will be compared to the standard reference hematology analyzer to determine if the overall average difference between each method and the standard reference is within 1.0g/dL.

For each child, study nurse/coordinator will: collect health information from the child, categorize skin pigmentation using the Massey and Martin NIS Skin Color Scale, measure and record finger diameter using the Masimo finger measuring tool (if none of the fingers are the appropriate size for the sensor, then the big toe will be measured and used instead). Capillary blood samples of the children will be taken via finger pricking of the third or fourth digit. If a child of 6-11 months is acutely malnourished (as determined by their weight-for-height Z score), the blood drop will be obtained from their heel in accordance with Hemocue® 201+ protocol and to ensure the finger bone is not injured due to insufficient finger padding. For both blood sampling locations, the first two drops of blood will be wiped away and only the third blood drop will be used. The randomization process and the data analysis phase will not be blinded.

To determine the accuracy of the noninvasive device, the difference between Hb values obtained from the Pronto® with DCI-mini™ sensory and standard reference hematology analyzer (Sysmex KN21™) will be calculated for each child and an average obtained. In addition to the mean difference (bias), the standard deviation, 95% confidence interval, range, and limits of agreement will also be obtained. Accuracy of Hb measurement by the noninvasive device will be assessed by determining whether the measurement obtained with each noninvasive device falls within ±1.0 g/dL of the standard reference. With 100 samples and assuming the correlation between measurement methods is at least 0.93, we have 97-99% power to confirm that the average difference between the two Hb measurement methods does not exceed 1.0 g/dL. This analysis will be conducted using a paired t-test since we will be testing a limit on the difference between the measures. The prevalence rate of anemia will also be estimated for the group from the noninvasive measurements in comparison to the standard reference measurements and analyzed by paired t-test. For this comparison, our sample size of 100 affords us enough power to determine if participants are correctly classified as anemic or not anemic, with less than 31% disagreement.

A similar process will be followed for each of the two HemoCue® Hb 201+ capillary blood collection methodologies in comparison to the standard reference hematology analyzer using a paired t-test to test the limit on the difference between measures. With 50 samples and assuming the correlation between measurement methods is at least 0.93, we again have 77-99% power to confirm that the average difference between each of the two Hb measurement methods and the standard reference does not exceed 1.0 g/dL. The prevalence rate of anemia will also be estimated for each of the HemoCue® 201+ study arms for comparison with the standard reference measurements and analyzed by paired t-test. For this comparison, our sample size of 100 enables us to test if participants are correctly classified as anemic or not anemic, with less than 35% disagreement.