Recent Outpatient Services in General Internal Medicine: 6.4% of Symptomatic Patients Were Post-Acute COVID-19.

Purpose: It is important to understand how COVID-19 is affecting general outpatient services, since hospitals see a wide variety of patients. This study aimed to evaluate the incidence and clinical picture of COVID-19 in general outpatient services. Currently, the diagnosis of COVID-19 depends strongly on the results of polymerase chain reaction (PCR) assays. However, since the sensitivity of PCR tests for SARS-CoV-2 is not high enough to assure confidence. On the other hand, the SARS-CoV-2 antibody (Ab) test is highly sensitive after 2 weeks of symptom onset, and might complement the PCR test. Therefore, we measured Ab in addition to PCR to obtain a more accurate clinical profile of COVID-19, which might be helpful in building future practice strategies. Patients: The study patients were those who visited our department for the first time between November 2020 and March 2021 and fulfilled the enrolment criteria. Methods: All patients underwent total SARS-CoV-2 Ab testing, and PCR tests were performed in only some of them; patients were classified according to the performance of PCR tests for comparisons. Results: Ninety-four patients who underwent Ab testing during the study period were eligible for study enrolment, and the PCR test was performed in 40 of them. Only one patient was diagnosed with acute stage COVID-19 based on a positive PCR test. Antibodies were positive in six (6.4%) of the 94 patients. Five of the six Ab-positive patients were negative for PCR, and the test was not performed in the sixth patient. All the six patients had prior symptoms suggestive of infection, and respiratory symptoms were more noticeable than fever. The Ab positivity rate was significantly higher than published data. Conclusion: COVID-19 is not rare in general outpatient services and can be missed based on PCR tests alone. The diagnosis should be made from a comprehensive perspective.