Expert Recommendations on Frequency of Utilization of Common Laboratory Tests in Medical Inpatients: a Canadian Consensus Study.

Background: Repetitive inpatient laboratory testing in the face of clinical stability is a marker of low-value care. However, for commonly encountered clinical scenarios on medical units, there are no guidelines defining appropriate use criteria for laboratory tests.

Objective: This study seeks to establish consensus-based recommendations for the utilization of common laboratory tests in medical inpatients.

Design: This study uses a modified Delphi method. Participants completed two rounds of an online survey to determine appropriate testing frequencies for selected laboratory tests in commonly encountered clinical scenarios. Consensus was defined as agreement by at least 80% of participants.

Participants: Participants were 36 experts in internal medicine across Canada defined as internists in independent practice for ≥ 5 years with experience in medical education, quality improvement, or both. Experts represented 8 of the 10 Canadian provinces and 13 of 17 academic institutions.

Main Measures: Laboratory tests and clinical scenarios included were those that were considered common on medical units. The final survey contained a total of 45 clinical scenarios looking at the utilization of six laboratory tests (complete blood count, electrolytes, creatinine, urea, international normalized ratio, and partial thromboplastin time). The possible frequency choices were every 2-4 h, 6-8 h, twice a day, daily, every 2-3 days, weekly, or none unless there was specific diagnostic suspicion. These scenarios were reviewed by two internists with training in quality improvement and survey methods.

Key Results: Of the 45 initial clinical scenarios included, we reached consensus on 17 scenarios. We reached weak consensus on an additional 19 scenarios by combining two adjacent frequency categories.

Conclusions: A Canadian expert panel of internists has provided frequency recommendations on the utilization of six common laboratory tests in medical inpatients. These recommendations need validation in prospective studies to assess whether restrictive versus liberal laboratory test ordering impacts patient outcomes.