Tadesse Lejisa

Objectives: Although the burden of syphilis is slightly increasing worldwide, there are a limited number of rapid, simple-to-use, accurate and cost-effective diagnostic tools available. Thus, we aimed to determine the diagnostic performance of theTreponema pallidumparticle agglutination (TPPA) test (hereafter called index test) against an electrochemiluminescence immunoassay (ECLIA) (hereafter called reference test). We selected the available treponemal reference test (ECLIA) to evaluate the index test (TPPA) which is not currently in use in Ethiopia.Methods: We conducted a multicentre cross-sectional study to evaluate the diagnostic performance of the index test against the reference test. We enrolled 581 syphilis-suspected cases from the five selected health facilities in Addis Ababa in this study. We collected data on sociodemographic and clinical characteristics and whole blood from each participant. We estimated the sensitivity, specificity and positive and negative predictive values of the index test.Results: Of the 581 participants, 380 (65.4%) were female. The mean age of the participants was 39.7 years (±SD 16.6), with an age range of 18–94 years. The sensitivity of the index test was 99.4% (95% CI 96.4% to 100%), while the specificity was 100%. The positive predictive value of the index test was 100%, and the negative predictive value was 99.8% (95% CI 98.4% to 100%). There was no invalid test result.Conclusions: The diagnostic performance of TPPA for syphilis was equivalent to that of ECLIA. Thus, TPPA can be used for the diagnosis of syphilis at the health facility level equivalent to a reference test.

Although nasopharyngeal swabs (NPSs) are superior to saliva specimens, saliva can be used as an alternative specimen for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. Moreover, studies have reported contradicting findings on whether SARS-CoV-2 can be detected in urine or not. Thus, we aimed to evaluate the diagnostic utility of NPSs, saliva and urine specimens in suspected COVID-19 patients. We conducted a cross-sectional study among a total of 604 specimens collected from 219 individuals suspected for COVID-19 from February to July 2022. We recruited participants from two COVID-19 isolation and treatment centers in Addis Ababa. We analyzed the specimens by real-time reverse transcriptase polymerase chain reaction (RT-PCR) with a Cobas 8800 automated system. The presence of SARS-CoV-2 in NPS, saliva, and urine samples was measured by cycle threshold (Ct) values. Descriptive statistics such as frequency, percent, and mean with standard deviation were used to summarize participants characteristics. We conducted chi-square test to compare RT‒PCR results of NPS, saliva and urine specimens. All data was analyzed by SPSS version 27, and the level of significance was set at a p value ≤ 0.05. Of the 219 participants, 126 (57.5%) were positive for SARS-CoV-2 either from NPS, saliva, urine or all specimens. The rate of SARS-CoV-2 detection was significantly higher in NPS (53.9%) than in saliva (35.2%; p = 0.001) and urine (9.0%; p = 0.001) specimens. The percentage of positive agreement between NPS and saliva was 92.2%, while negative agreement was 66.9%. The overall agreement between NPS and saliva was 75.8% (K = 0.53, p < 0.001). In addition, there was a significant correlation in Ct values of both ORF1ab and E genes between the paired NPS and saliva specimens. There was significant positive correlation between NPS and saliva specimens Ct values of both ORF1ab and E genes and days from onset of symptoms to specimen collection. SARS-CoV-2 was significantly detected in NPS than in saliva and urine specimens. Although NPS is better for SARS-CoV-2 detection, saliva specimen can be used as an alternative clinical specimen in resource-limited settings where access to swabs is limited. Both saliva and urine could be sources of viral transmission.

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