Background: The utility of procalcitonin (PCT) in pediatrics is debated. Proposed diseases in which PCT elevation is thought to be suggestive of a bacterial process include meningitis, urinary tract infection, pneumonia, neonatal fever, and sepsis of unknown source. However, elevated PCT is non-specific for bacterial infection and the strength of the test is generally felt to be its high negative predictive value. There is little understanding of how PCT testing is being used by providers in the hospital setting. We examined patterns of PCT testing in children hospitalized at a tertiary care Children’s Hospital.
Methods: We used laboratory data to identify children hospitalized between 1/1/2017 and 6/30/2019 who had PCT testing obtained at least one time during their admission. Variables of interest included the service of the ordering provider, location of the patient at time of testing, patient age, and procalcitonin value. We analyzed the top 2% of patients with the most PCT testing. Procalcitonin values were categorized as diagnostically low if the value was ≤0.1 and diagnostically elevated if the value was >0.5, as defined by hospital guidelines.
Results: 4135 PCT tests were sent on 1530 children. 865 children were tested only once, of which 280 (32.4%) were diagnostically elevated. Of all tests sent, 982 (23.7%) were diagnostically low and 1993 (48.1%) were diagnostically elevated. PCT testing was sent most frequently by pediatric intensive care (PICU) providers (41.4% of all tests) and hospital medicine providers (20.4% of all tests). The most common hospital unit for testing was the cardiac intensive care unit, which accounted for 21.7% of all testing. The average number of tests per patient was 3 and the median number of tests per patient was 1. The top 2% of patients for number of tests ordered (31 children) accounted for 20% of all tests done; 8% of these were diagnostically low.
Conclusions: In this retrospective study of PCT testing in children hospitalized at a tertiary care Children’s Hospital, we found that a very small number of patients accounted for a large portion of the testing sent and, in those frequent users, the large majority of tests are abnormal. The PICU and hospital medicine providers ordered more than 60% of the testing done in the hospital while surgical and medical subspecialties were less likely to utilize the test. More than 30% of patients had a diagnostically elevated PCT that was not repeated within the admission, which represents an opportunity to improve utilization with serial testing. A closer evaluation of the real-world practices of PCT testing, including a more in-depth analysis of antibiotic use following the report of a diagnostically low value in patients, is warranted to determine how the test is being used in pediatric populations.