Field evaluation of specificity and sensitivity of a standard SARS-CoV-2 antigen rapid diagnostic test: A prospective study at a teaching hospital in Northern Ghana

Abstract

Background: The testing capacity for SARS-CoV-2 in Africa is rather limited. Antigen-detection rapid diagnostic tests (Ag-RDTs) are a cheap and rapid alternative to reverse transcriptase-polymerase chain reaction (RT-PCR) tests, but there is little data about their performance under real life conditions in tropical countries. Objective: To evaluate the performance of a standard Ag-RDT in a population of a major hospital in northern Ghana. Methods: Prospective, cross-sectional, blinded verification of the performance of the SD Biosensor Standard Q SARS-CoV-2 Ag-RDT under real life conditions in 135 symptomatic patients and 58 contacts of RT-PCR positives at Tamale Teaching Hospital in February 2021. Nasopharyngeal samples were taken under standard conditions and tested against RT-PCR in the hospital laboratory. Results: 193 participants (median age 35 years, 109 male) were included into the study for which both RT-PCR test and Ag-RDT results were available. A total of 42 (22%) were RT-PCR-positive. Of the 42 RT-PCR-positives, 27 were Ag-RDT positive, resulting in a sensitivity of 64% (95% CI 49-79). Sensitivity among symptomatic patients was 58% (95% CI 38-78). 123 were identified Ag-RDT negatives of the 151 RT-PCR negatives, resulting in a specificity of 81% (95% CI 75-87). Conclusions: SARS-CoV-2 Ag-RDTs appear to have a rather low sensitivity and particularly a low specificity under real life conditions in Africa. The role of existing Ag-RDTs in countries with high-temperature climates and limited resources still needs more data and discussion.

Accuracy of rapid point-of-care antigen-based diagnostics for SARS-CoV-2: An updated systematic review and meta-analysis with meta-regression analyzing influencing factors

“…At the end of the data extraction process, 21 studies were still in preprint form [20,21,25,51,54,59,62,69,73,78,88,104,120,125,133,164,171,172,177,178,190]. All studies included were written in English, except for 3 in Spanish [57,66,138], 1 in Turkish [99], and 1 in French [157].…”

Field clinical performance of SARS-CoV-2 point-of-care diagnostic tests: a living systematic review of trials up to 17th of August, 2021

“…This finding is significant and may partially explain false negative results, considering that many regions have oscillations in temperature outside the target range and some factors like stock storage and transportation are beyond the end-user control. In this context, Abdul-Mumin et al 138 reported suboptimal results for both sensitivity and specificity using the STANDARD Q COVID-19 test (64% and 81%, respectively); authors reported the difficulty of maintaining the tests within the ideal temperature range near patients given the temperatures in Ghana, despite following the manufacturer’s storage conditions. Therefore, for optimal results, it is important to consider not only the performance of the tests but also context they are being used in.…”

Update of European Society of Clinical Microbiology and Infectious Diseases coronavirus disease 2019 guidelines: diagnostic testing for severe acute respiratory syndrome coronavirus 2

“… In patients with signs and symptoms compatible with COVID-19, we suggest the use of laboratory based NAAT in nasopharyngeal samples versus rapid antigen detection testing in nasopharyngeal samples for the diagnosis of COVID-19. Weak against Very low [ 4 , 5 , 16 , 106 , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , 6 , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , 8 , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , 10 , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , 11 , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] ...…”

“… In patients with signs and symptoms compatible with COVID-19 of equal or less than 7 days-onset, we suggest the use of rapid antigen detection testing versus laboratory-based NAAT for the diagnosis of COVID-19. Weak for Very low [ 3 , 7 , 39 , 41 , 46 , 53 , 60 , 61 , 63 , 65 , 73 , 78 , 9 , 79 , 83 , [91] , [92] , [93] , 96 , 97 , 100 , 101 , 104 , 11 , 106 , 108 , 109 , 114 , 118 , 119 , 126 , [129] , [130] , [131] , 13 , [132] , [133] , [134] , [135] , [136] , 14 , 17 , 21 , 36 , 37 ] 16 In patients with signs and symptoms compatible with COVID-19 of more than 7 days-onset , should rapid antigen detection testing be used, compared with standard NAAT (commercial and/or in house) for diagnosis of COVID-19? In patients with signs and symptoms compatible with COVID-19 of more than 7 days-onset, we suggest the use of laboratory-based NAAT versus rapid antigen detection testing for the diagnosis of COVID-19.…”

“… In patients ≥ 12 years old with signs and symptoms compatible with COVID-19, we suggest the use of laboratory-based NAAT versus rapid antigen detection testing for the diagnosis of COVID-19. Weak against Low [ 4 , 6 , 25 , 28 , 33 , 34 , 37 , [41] , [42] , [43] , [44] , 46 , 7 , 48 , 49 , [53] , [54] , [55] , [62] , [63] , [64] , 70 , 71 , 10 , 77 , 82 , 83 , 90 , 94 , 108 , 109 , 111 , 113 , 115 , 11 , 116 , 119 , 123 , 128 , 130 , 133 , [135] , [136] , [137] , 140 , 17 , [143] , [144] , [145] , [146] , [147] , [148] , [149] , [150] , [151] , ...…”