There is a high rate of false negatives with rapid serology tests for SARS-CoV-2, is there an alternative method to determine positive cases?
A high rate of false negatives with antigen point-of-care assays may be due to the fact that the majority of patients produce antibodies against SARS-CoV-2 only after the second week after of infection.103 Furthermore, an effective antibody response is connected with several determinants, comprising severity of the disease, age and nutritional status of the patient, medications administered and concomitant infections.102 Nucleic acid amplification using RT-PCR directly targeting the virus is not affected by the above-mentioned limitations.104However, false-negative real-time RT-PCR tests for the diagnosis of SARS-CoV-2 were reported by Zhang et al . in a retrospective study of 290 hospitalized and confirmed COVID-19 patients in Wuhan, China. Forty-one of them initially tested negative for SARS-CoV-2 and 21/41 tested positive by the second real-time RT-PCR test and an additional 13/41 patients by the third test. Almost all patients (98%) tested positive by the fifth and final test.105 Patients with an initial positive SARS-CoV-2 result had an increased risk of progressing to severe cases. Altogether, these findings underscore how the timing of the immune response influences RT-PCR tests for SARS-CoV-2, and the importance of combining RT-PCR data with seroconversion for COVID-19 diagnosis.