Laboratory practice of reference intervals modification for children's blood cell analysis in China

Background: The unreliability of reference intervals (RIs) for children’s blood cell analysis has led to an unnecessary effort in interpreting results. The Standard published in 2021 is expected to solve this problem in China but should be clinically evaluated before its application. Methods: Compared with the laboratory’s original RIs, the RIs’ numerical trends were mapped and analyzed, and the data of the past seven years were retrospectively re-interpreted. Pediatricians were then consulted to discuss the data analyses. Results: The new RIs were summarized as follows: 1) The age stratification is more detailed; 2) The venous blood and peripheral blood are characterized; 3) The numerical range was relatively more comprehensive, and some parameters were unilaterally shifted. Retrospective analysis showed that the revised RIs could correct previously abnormal results to the normal range in a large proportion. The recovery ratio of three lineage cells was white blood cells > red blood cells > platelets, and the ratio sorted by age is 28 days~1-year-old > 1~13years old > 13~18 years old. The leukocyte recovery ratio of 28 days~1 year was the largest, approximately 55% to 83%. Pediatricians recognized the value of the new RIs. The only exception is that the platelets’ RIs were too broad, recommending maintaining the original RI. The missing 0~28 days RIs were recommended to be supplemented with other reference books. Conclusions: The new RIs were optimized and, combined with clinical feedback, produced new RIs derived from accumulated experience, evolving a better set of RIs.