Evaluation of the AMP SARS-CoV-2 rapid antigen test in a hospital setting

Abstract

Objectives: Quick and inexpensive SARS-CoV-2 screening and frontline testing are in growing demand. Our study aimed to evaluate the performance of the immunochromatographic AMP rapid antigen test (AMP RAT) compared to the gold-standard real-time reverse transcription PCR (rRT-PCR) in a hospital cohort.

Methods: A total of 392 patients, who presented consecutively with COVID-19 symptoms in our emergency department, were included in this retrospective study. Two swabs were collected per patient: a nasopharyngeal for the RAT and a combined naso- and oropharyngeal for the rRT-PCR. A positive rRT-PCR (defined as cycle threshold (Ct) < 40) was found in 94 (24%) patients.

Results: In our cohort with a median patient age of 70, overall sensitivity and specificity of the AMP RAT was 69.2% (58.8-78.3, 95% CI) and 99.7% (98.1-100.0, 95% CI), respectively. In patients with a Ct value < 25 and < 30, higher sensitivities of 100.0% (89.4-100.0, 95% CI) and 91.8% (81.9-97.3%, 95% CI) were observed.

Conclusions: The AMP RAT showed a high sensitivity in patients with a Ct value < 25 and < 30 and might be helpful for frontline testing whenever rRT-PCR is not readily available.

Keywords: COVID-19; Coronavirus; Diagnosis; Screening; rRT-PCR.

Graphical abstract

Figure 1

Schematic representation of the AMP test and result possibilities. Positive: two colored stripes appear on the membrane; one stripe appears in the control area and another stripe in the test area; the color intensity of the stripe may vary depending on the concentration of SARS-CoV-2 antigen in the sample; therefore, every shade of color in the test area was regarded as a positive result. Negative: only one colored strip appears in the control area. Invalid: if no colored stripe appears in the control area, the test is invalid.