Different interpretations of inconclusive results of SARS-CoV-2 real-time RT PCR

You La Jeon; Sang Gon Lee; Eun Hee Lee; Sungwook Song; Un Young Go; Ga-Young Chun

doi:10.1016/j.diagmicrobio.2022.115888

Different interpretations of inconclusive results of SARS-CoV-2 real-time RT PCR

Diagn Microbiol Infect Dis. 2023 Jun;106(2):115888. doi: 10.1016/j.diagmicrobio.2022.115888. Epub 2023 Jan 4.

Authors

You La Jeon¹, Sang Gon Lee², Eun Hee Lee³, Sungwook Song¹, Un Young Go⁴, Ga-Young Chun⁴

Affiliations

¹ Department of Laboratory Medicine, Green Cross Laboratories, Yongin-si, Korea.
² Department of Laboratory Medicine, Green Cross Laboratories, Yongin-si, Korea. Electronic address: sglee@gclabs.co.kr.
³ Department of Laboratory Medicine, Green Cross Laboratories, Yongin-si, Korea. Electronic address: ehlee@gclabs.co.kr.
⁴ Infectious Diseases Research Center, Green Cross Laboratories, Yongin-si, Korea.

Abstract

We investigated whether inconclusive results could be interpreted differently depending on the situation. First, data from retesting of the initial samples from subjects without a confirmed COVID-19 history were analyzed. And by analyzing the results of consecutive tests with new specimens after receiving inconclusive results between arrivals and locals for 2 periods. As a result, 179 of 219 cases (81.7%) showed still inconclusive or weakly positive results. If contamination is well controlled in a general laboratory, the effectiveness of retesting with the same sample is limited. The rate of the subsequently positive patient was significantly higher in locals than in arrivals and periods with a higher positive rate. The inconclusive results could be interpreted differently depending on the epidemiologic background and the positive rate at that time.

Keywords: COVID-19; Inconclusive result; SARS-CoV-2 real-time RT PCR.

MeSH terms

COVID-19 Testing
COVID-19* / diagnosis
Humans
Laboratories
Reverse Transcriptase Polymerase Chain Reaction
SARS-CoV-2* / genetics