Optimized Delta Check Rules for Detecting Misidentified Specimens in Children

Rui Zhen Tan, Corey Markus, Kay Weng Choy, James C.G. Doery, Tze Ping Loh

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Objectives: Preanalytical processes in pediatric patients are generally manual and associated with a higher risk of error. The optimized delta check rules for detecting misidentified children samples are examined. Methods: Relative difference and absolute different delta check limits were applied on original and reshuffled (to simulate sample mislabeling/mix-up) paired deidentified pediatric results of 57 laboratory tests. The sensitivity, specificity, and accuracy of a range of delta check limits were determined. The delta check limit associated with the highest accuracy was considered optimal. Results: In general, the delta check limits had poor to moderate accuracy (0.50-0.81) in detecting misidentified patient samples. The sensitivity (rule out misidentified sample) quickly deteriorated at increasing delta check limits. At the same time, the specificity (rule in misidentified sample) of the delta check limit was also low. The performance of the relative difference and absolute difference delta check rules was similar. Conclusions: Our findings showed poor delta check performance in the pediatric population. The high false-positive flag rate may lead to wasteful resource-intensive investigations and delay in result reporting. In addition, we observed that the optimized pediatric delta check correlated strongly with within-subject biologic variation, whereas delta check accuracy correlated poorly with index of individuality.

Original languageEnglish
Pages (from-to)605-612
Number of pages8
JournalAmerican Journal of Clinical Pathology
Issue number5
Publication statusPublished - May 2020
Externally publishedYes


  • Children
  • Delta check
  • Pediatric
  • Preanalytical error
  • Sample mix-up
  • Wrong blood in tube


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