Prognostic value of labs ordered on patients hospitalized with COVID-19

ABSTRACT

Background: Hospitalists at our institution have taken on most non-intensive care unit (ICU) coronavirus disease 2019 (COVID-19) care. Based on sparse research, our institution developed a protocol for ordering labs for this patient population, including routine admission labs in addition to eight COVID-19-specific daily labs. The study goal is to determine if COVID-19-specific admission labs have any prognostic value beyond that provided by routine admission labs and vitals, and costs of labs with no prognostic value.

Methods: We retrospectively reviewed adult patients admitted with COVID-19 from 3/2020 to 7/2020. Outcomes were mortality, ICU stay, and length of hospitalization. Multivariable logistic and linear regression were used to determine if COVID-19-specific admission labs have any prognostic value beyond that provided by vitals and routine admission labs. COVID-19-specific labs were d-Dimer, fibrinogen, ferritin, LDH, CK, pro-BNP, troponin, and CRP. Multivariable models included all routine admission labs and vitals. COVID-19-specific admission labs were included in the multivariable models if the p-value was <0.05 in the univariable analysis.

Results: 331 patients met study criteria, inpatient mortality was 13.0%, 52.4% of patients required ICU stays and the average length of hospitalization was 8.9 days. COVID-19-specific labs showed no additional prognostic value for mortality. CRP, LDH, and d-Dimer provided additional prognostic information for ICU stay. CRP≥100 mg/dL and LDH≥900 U/L were associated with increased length of hospitalization.

Conclusion: Only 3 of 8 admission COVID-19-specific labs recommended by our institution’s protocol had additional prognostic value beyond that provided by routine labs and vitals. The total cost of non-prognostic COVID-19-specific labs during the study period was $75,874.

KEYWORDS:

• COVID-19
• quality improvement
• cost of care
• lab tests

Declaration of interest

The contents of the paper and the opinions expressed within are those of the authors, and the authors decided to submit the manuscript for publication.

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

We’d like to acknowledge contributions from Dr. Edward Hu for providing information on costs of laboratory tests.

Data sharing

The data that support the findings of this study are available from the corresponding author, CM, upon reasonable request.

Additional information

Funding

No funding was received to produce this article.