SARS-CoV-2 RT-qPCR Test Detection Rates Are Associated with Patient Age, Sex, and Time since Diagnosis

Area of Science:

• Virology
• Epidemiology
• Diagnostic testing

Background:

• Quantitative reverse transcription PCR (RT-qPCR) is crucial for detecting SARS-CoV-2.
• Understanding RT-qPCR test reliability across patient demographics and disease stages is vital for public health strategies.

Purpose of the Study:

• To quantify the detection rate of RT-qPCR for SARS-CoV-2.
• To assess the influence of patient demographics, disease progression, and viral RNA load on RT-qPCR test accuracy.

Main Methods:

• Analysis of 843,917 RT-qPCR test results from 521,696 patients diagnosed with COVID-19.
• Definition of a "positive period" to estimate detection rates.
• Regression analyses to identify associations between detection rates and time post-diagnosis, demographics, and viral RNA copy number (cycle threshold values).

Main Results:

• The overall RT-qPCR detection rate within 14 days of diagnosis was 83.1%, peaking at 89.3% between days 0-5.
• Detection rates were significantly associated with patient age and sex.
• The Allplex 2019-nCoV RT-qPCR kit's detection rate correlated with viral RNA copy number (P < 10^-9).

Conclusions:

• RT-qPCR test reliability diminishes in later stages of infection.
• Women and younger patients exhibit lower detection rates, linked to typically lower viral loads.
• These findings impact the interpretation of RT-qPCR results for epidemiological surveillance and patient management.