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.