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Relative criticalness of common laboratory tests for critical value reporting
  1. Zhutian Yang1,
  2. Eng Hooi Tan2,
  3. Yingda Li3,
  4. Brian Lim4,5,
  5. Michael Patrick Metz6,
  6. Tze Ping Loh5,7
  1. 1 School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
  2. 2 Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
  3. 3 Department of Industrial Systems Engineering and Management, National University of Singapore, Singapore, Singapore
  4. 4 Department of Computer Science, National University of Singapore, Singapore, Singapore
  5. 5 Biomedical Institution for Global Health and Technology, National University of Singapore, Singapore, Singapore
  6. 6 SA Pathology, The Women's & Children's Hospital, Adelaide, South Australia, Australia
  7. 7 Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
  1. Correspondence to Dr Tze Ping Loh, Department of Laboratory Medicine, National University Hospital, Singapore 119074, Singapore; tploh{at}


We determined the relative strengths of association between 23 most commonly ordered laboratory tests and the adverse outcome as indicators of relative criticalness. The lowest and highest results for 23 most commonly ordered laboratory tests, 24 hours prior to death during critical care unit (CCU) stay or discharge from CCU were extracted from a publicly available CCU database (Medical Information Mart for Intensive Care-III). Following this, the Random Forest model was applied to assess the association between the laboratory results and the outcomes (death or discharge). The mean decrease in Gini coefficient for each laboratory test was then ranked as an indication of their relative importance to the outcome of a patient. In descending order, the 10 laboratory tests with the strongest association with death were: bicarbonate, phosphate, anion gap, white cell count (total), partial thromboplastin time, platelet, total calcium, chloride, glucose and INR; moreover, the strength of association was different for critically high versus low results.

  • critical value
  • critical results
  • critical reporting
  • panic value
  • post-analytical

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  • Handling editor Prof Tahir S Pillay.

  • Contributors ZY, MPM and TPL conceived and designed the study. ZY, EHT and YL extracted the laboratory data. ZY, EHT, YL and BL analysed the data. TPL wrote the first draft. ZY, EHT, YL, MPM and BL critically reviewed the draft and provided additional inputs. All authors have read the final draft and approved of its submission.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.