Abstract: Objective To analyze the effect of different packed red blood cells (pRBCs) volume on the result of acid elution test, for optimizing the sample volume in neonatal hemolytic disease detection. Methods One hundred and fifty specimens with suspected neonatal hemolytic disease were collected from February 2022 to December 2022 for hemolytic triple test. We identified the elution agglutination intensity of specimens confirmed ABO neonatal hemolytic disease under four different pRBCs volume (A: 250 μL, B: 500 μL, C: 750 μL, D: 1 000 μL). Cochran's Q test was used to analyze the differences in overall positive rates among four groups. McNemar's test was applied for multiple comparisons. The Friedman test was used to analyze the differences in the overall distribution of agglutination intensity, and the Wilcoxon test was applied for multiple comparisons. Results In 118 cases of confirmed ABO neonatal hemolytic disease, the positivity rate was 94.92% in group A, and 100% in groups B, C, and D (P<0.05).There was no significant difference in positive rate between group A and groups B/C/D (corrected P>0.008 3). The overall difference (P<0.001) and the multiple comparison difference (P<0.008 3 after correction) in the rank distribution of agglutination intensity for the four groups were statistically significant, and the agglutination intensity increased with the increase of pRBCs volume. Conclusion We can reduce the pRBCs volume from 1 000 μL to 500 μL in acid elution test, ensuring the accuracy of the test results and saving blood sample volume.

Key words: ABO Neonatal hemolytic disease, Acid elution test, Packed red blood cells, Agglutination intensity