Immunochip for Syphilis Serodiagnostics with the Use of Extended Array of Treponema pallidum Recombinant Antigens.

An immunochip for multiple parallel detection of specific serum IgG in serological screening for syphilis is based on the use of an extended array of Treponema pallidum recombinant proteins and includes traditionally used immunodominant antigens (Tp15, Tp17, Tp47, and TmpA) and new synthetic proteins (Tp0277, Tp0319, Tp0453, Tp0684, Tp0965, and Tp1038). The use of individual antigens has demonstrated high analytical value of Tp0277 (periplasmatic C-terminal protease), Tp0319 (cytoplasmic membrane-associated lipoprotein TmpC), and external membrane-associated protein Tp0453 with transporting function, all of them improving significantly the efficiency of screening for syphilis in comparison with the traditional array of antigens. Multiparametric analysis of the results obtained on the immunochip with the use of linear discriminant analysis confirmed the efficiency of extended array of T. pallidum diagnostic antigens. Due to proposed modification, the "positive" and "negative" sera are clearly differentiated: the serological study showed 94.1% sensitivity and 100% specificity.

Field evaluation of a smartphone-based electronic reader of rapid dual HIV and syphilis point-of-care immunoassays.

OBJECTIVE: Electronic (E) devices read and quantify lateral flow-based rapid tests, providing a novel approach to assay interpretation. We evaluated the performance of one E-reader for two dual HIV and syphilis immunoassays. METHODS: We enrolled men who have sex with men and transgender women >18 years of age seeking medical services at an STD clinic in Lima, Peru, between October 2016 and April 2017. Venous blood was tested using two dual HIV and syphilis antibody immunoassays (SD BIOLINE HIV/Syphilis Duo, Republic of Korea, and First Response HIV 1+2/Syphilis Combo, India). Reference testing included a fourth-generation ELISA for HIV antibodies and use of the Treponema pallidum particle agglutination assay for syphilis antibodies. Trained clinic staff visually inspected the immunoassay results, after which the immunoassays were read by the HRDR-200 E-reader (Cellmic, USA), an optomechanical smartphone attachment. We calculated the concordance of the E-reader with visual inspection, as well as the sensitivity of both rapid immunoassays, in detecting HIV and T. pallidum antibodies. RESULTS: On reference testing of 283 participant specimens, 34% had HIV antibodies and 46% had T. pallidum antibodies. Using First Response, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T.pallidum and 97% (95% CI 95% to 99%) for HIV antibodies. Using SD BIOLINE, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T. pallidum and 99% (95% CI 98% to 99%) for HIV antibodies. For both immunoassays, the sensitivity for HIV antibodies was 98% (95% CI 93% to 100%) and the sensitivity for T. pallidum antibodies was 81% (95% CI 73% to 87%). CONCLUSIONS: E-reader results correlated well with visual inspection. The sensitivities of both rapid assays were comparable with past reports. Further evaluation of the E-reader is warranted to investigate its utility in data collection, monitoring and documentation of immunoassay results.

Comparison of Manual and Fully Automated AIX1000 Rapid Plasma Reagin Assays for Laboratory Diagnosis of Syphilis.

The analytical performance of the AIX1000 system, a fully automated and recently FDA-cleared rapid plasma reagin (RPR) system, was evaluated by comparison to a manual RPR test in a traditional syphilis testing algorithm. A total of 1,028 consecutive serum samples submitted for syphilis testing to the University of North Carolina Hospitals Clinical Immunology Laboratory were tested per each manufacturer's instructions. Among those samples, 996 were nonreactive and 20 were reactive using both the ASI RPR card system and the AIX1000 system. Of the 12 discrepant specimens, 11 were AIX1000 reactive and ASI card nonreactive whereas 1 specimen was ASI card reactive and AIX1000 nonreactive. The sensitivity and specificity of the manual ASI card were 76.0% and 99.8%, respectively, while the sensitivity and specificity of the AIX100 were 100.0% and 99.4%, respectively (sensitivity P = 0.03). Among the 20 concordant reactive specimens, 68.4% of the titers agreed within ±1 dilution between methods. Reproducibility testing of the AIX1000 system demonstrated qualitative and semiquantitative (within ±1 dilution) agreement between specimens tested on different days of 96.0% and 76.0%, respectively, and 100.0% agreement between replicates within the same run. One of 24 samples analyzed under other disease conditions was reactive on both the AIX1000 system and the ASI card. Overall, the fully automated AIX1000 system demonstrated significantly enhanced sensitivity and specificity similar to that of the manual ASI RPR card test, making the AIX1000 system suitable for the laboratory diagnosis of syphilis in a clinical laboratory setting.

Rapid diagnostic testing to improve access to screening for syphilis in prison.

OBJECTIVES: To assess the accuracy of on-site rapid treponemal test for syphilis diagnosis in women deprived of liberty in Bolivia. MATERIAL AND METHODS: Serological tests for syphilis were performed on 219 women deprived of liberty from the San Sebastián prison in Cochabamba, Bolivia. Syphilis was diagnosed using RPR (bioMérieux) and TPPA (Fujirebio) serological tests, and the results were compared to on-site rapid treponemal test (Alere DetermineTM Syphilis TP) in whole blood. Diagnostic performance of two FTA tests were also compared (bioMérieux and Biocientífica). RESULTS: All participants (28) with RPR+/TPPA+ had the rapid syphilis test positive (sensitivity 100%). Eleven participants had rapid syphilis test positive without RPR and TPPA both positive; nevertheless 7 of them had RPR or TPPA positive. Of 33 participants with FTA-bioMérieux positive, 22 (66.6%) had FTA-Biocientífica positive. DISCUSSION: The rapid syphilis test Determine shows excellent performance as a screening tool among women deprived of liberty affected by high prevalence of syphilis. This test is particularly indicated when there are barriers for access to conventional serological tests. It is inexpensive, easy to use and does not require electricity and laboratory infrastructure. The FTA test performed with reagents from Biocientífica had a suboptimal sensitivity.

Laboratory evaluation of three dual rapid diagnostic tests for HIV and syphilis in China and Nigeria.

OBJECTIVE: To determine the laboratory-based performance and operational characteristics of three dual rapid diagnostic tests (RDTs) for testing HIV and syphilis. METHODS: Three dual RDTs (SD Bioline, Chembio, and MedMira) were evaluated using 1514 serum specimens archived at laboratories or collected from clinics in China and Nigeria to determine sensitivity and specificity, with 95% confidence intervals. Concordance of testing results read by two technicians, stability of testing results read at two time points, and test operation characteristics were also assessed. RESULTS: All three of the evaluated RDTs gave excellent performance with a combined sensitivity ranging from 99.0%-99.6% for HIV and 98.3%-99.0% for syphilis, and a combined specificity ranging from 97.9%-99.0% for HIV and 97.2%-99.6% for syphilis. Concordance of testing results between two technicians and stability of testing results read within and one hour past the recommended reading period showed excellent agreement, with Kappa greater than or equal to 0.98. CONCLUSIONS: All the tests were found to be very or fairly easy to use and easy to interpret the results. Further evaluations of these dual RDTs with whole blood in field settings, and more studies on the implication of introduction of these tests in HIV and syphilis control programs are needed.

The diagnostic performance evaluation of the SD BIOLINE HIV/syphilis Duo rapid test in southern Ethiopia: a cross-sectional study.

OBJECTIVE: To determine the diagnostic performance of the SD BIOLINE HIV/syphilis Duo rapid test. DESIGN: A hospital-based cross-sectional study. SETTING: This evaluation was conducted at one of the largest hospitals in southern Ethiopia. PARTICIPANTS: Serum samples obtained from clients attending the antiretroviral therapy and voluntary counselling and testing centres were used. Sera were originally collected for the purpose of investigating syphilis epidemiology. The performance of the test to detect HIV was evaluated using 400 sera (200 HIV positives and 200 HIV negatives). Also, its performance to detect syphilis was evaluated using 85 syphilis positive and 100 syphilis negative serum samples. Individuals <15 years of age or syphilis treated or those with ≤50 cells/µL CD4 cell count were originally excluded. OUTCOME MEASURES: HIV screening was carried out according to the national rapid diagnostic testing (RDT) algorithm: Shenghai Kehua Bioengineering (KHB) test kit as a screening test, followed by the HIV1/2 STAT-PAK assay if positive. Where the result of the STAT-PAK is discordant with KHB, Unigold HIV is used as a tiebreaker to determine the result. We also used ELISA to resolve discordant HIV results. Syphilis serostatus was determined using the Treponema pallidum haemagglutination assay (TPHA). RESULTS: The respective sensitivity, specificity, positive predictive value and negative predictive value of the SD BIOLINE HIV/syphilis Duo test were 100, 99.5, 99.5 and 100% for HIV and 97.6, 96, 95.4 and 98% for syphilis testing, respectively. In reference to TPHA, the test kit reported 4 false positives and 2 false negative results for syphilis. The κ values were 0.99 for HIV testing and 0.94 for syphilis testing. CONCLUSIONS: The excellent performance of the SD BIOLINE HIV/syphilis Duo test to detect HIV as well as syphilis facilitates the integration of syphilis testing and treatment to the already established HIV prevention programme, ultimately contributing to the dual HIV and syphilis elimination goal.

Performance of Liaison XL automated immunoassay platform for blood-borne infection screening on hepatitis B, hepatitis C, HIV 1/2, HTLV 1/2 and Treponema pallidum serological markers.

OBJECTIVES: Aim of the study was to evaluate performance of a new fully automated platform, DiaSorin-LIAISON® XL (DiaSorin S.p.A, Vercelli, Italy), in blood donor screening, specifically for hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc), hepatitis C antibodies (anti-HCV), HIV p24 antigen, HIV antibodies, human T-lymphotropic virus types 1 and 2 (HTLV-1/2) and Treponema pallidum antibodies. BACKGROUND: In screening for such viral and bacteriological blood-borne infections, sensitivity and specificity are of utmost importance. METHODS: Sensitivity was evaluated using selected panels of samples previously analysed on the Abbott Architect immunoanalyser (Abbott Laboratories, Abbott Park, IL, USA)--the gold standard for this evaluation. These samples were confirmed positive for HBsAg, anti-HBc, anti-HCV, HIV Ag/Ab, anti-HTLV-1/2 and antibodies to T. pallidum, respectively. Specificity analysis was assessed by analysing blood donor samples previously run on the Architect platform and found non-reactive for each marker. A total of 1·100 donor samples (both new and regular donors) were tested. Previously, non-specific reactive samples were also run for every tested marker, as well as samples with autoimmune antibodies and antibodies to other infections. RESULTS: Three hundred seventy-eight samples positive for the tested markers (HBsAg n = 51, anti-HBc n = 52, anti-HCV n = 75, anti-Treponema n = 55, anti-HIV-1 n = 79, anti-HIV-2 n = 25, anti-HIV 1/2 n = 3, anti-HTLV-1 n = 28 anti-HTLV-2 n = 10) were tested and found positive, suggesting a high sensitivity. A number of 342-1100 negative blood donors (depending on marker) have been tested, with very good specificity for the markers tested, ranging between 99·5 and 100%, respectively. CONCLUSIONS: The LIAISON® XL platform demonstrated very high sensitivity for the markers tested and the specificity necessary to fulfil the stringent requirements for blood donor screening.

Evaluation of the SD Bioline HIV/Syphilis Duo assay at a rural health center in Southwestern Uganda.

BACKGROUND: Point-of-care tests have the capacity to improve healthcare delivery by reducing costs and delay associated with care. A novel point-of-care immunochromatographic test for dual diagnosis of both HIV and syphilis by detecting IgG, IgM and IgA antibodies to HIV, and specific and recombinant Treponema pallidum antigens has recently been developed, but has not been evaluated in rural field settings. We evaluated the performance of the SD Bioline Syphilis/HIV Duo (Duo) assay at a healthcare center in rural Uganda. METHODS: A convenience sample of pregnant women attending Kinoni Health Centre IV from March to May, 2013 was enrolled. Venous blood was collected and centrifuged for plasma isolation. Samples were tested with the Duo assay and compared with the Treponema pallidum hemaglutination assay and paired HIV rapid antibody tests as the reference standards. The ease of use and time required for the Duo assay were also assessed by laboratory technicians. RESULTS: Two hundred twenty women were enrolled with a mean age of 25.00 years (SD 5.41). The sensitivity and specificity of the Duo assay were 100% (95% CI 79.0 - 100%) and 100% (95% CI 97.6 - 100.0) respectively, for syphilis, and, 100% (75.9 - 100%) and 99.5% (96.8 - 99.9%) respectively, for HIV. The duo kit was found to be faster and easier to use than the current HIV and syphilis testing techniques. CONCLUSION: The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo test were excellent in a field setting in Uganda. The Duo assay should be further evaluated in alternate populations and with point-of-care specimens (e.g. whole blood from finger stick specimens), but shows promise as a tool for improved HIV and syphilis surveillance, diagnosis, and treatment in field settings.

Innovative accountability of tracking test kit as locked resources: a lesson in a restricted resource setting.

BACKGROUND: To implement quality screening in a blood service requires the presence of screening strategy with a clear algorithm and supporting standard operating procedures (SOPs), skilled and motivated human resource to perform testing, infrastructure, regular available test kits, and other supplies. In developing countries, smooth supply chain management of critical transfusion transmissible infections (TTIs) screening reagents is a challenge. Therefore, managing the little available kits by knowing the rate of consumption, good forecasting, and monitoring expiry date may be a key in ensuring regular supply. METHOD: Test kit monitoring tool (TKMT) for Vironostika HIV Uni-Form kit/192 1&2 Ag/Ab, Genedia kits for HBsAg and HCV, and RPR for syphilis was developed to track these reagents. This excel tool was developed to assess received reagents, quantity used, quantity remaining, and date of expiration. The tool was evaluated by assessing rerun for each test kits, match tests conducted with blood units tested, adherence to the principle of first in-first out (FIFO), and quantity remaining in the center against the need. RESULTS: The mean rerun for HIV ELISA Vironistika uniform II Ag/Ab observed over expected was 6.9% (n = 3.8) than 2.4% (n = 1.3), HBsAg was 9.9% (n = 5.7) than 6.7% (3.5) (expected), Genedia for HCV was 1.3% (n = 0.7) than 0.5% (n = 0.3), and RPR test for syphilis 3.3% (n = 1.5) than 0.5%. During implementation, TKMT managed to detect expiring kits in the zonal blood transfusion centers. CONCLUSION: A tool-like TKMT may capture other supplies within blood when expanded. Monitoring of supplies may enable blood service actual accounting and in forecasting supplies and reagents.

Aportación de las pruebas serológicas automatizadas en el diagnóstico de sífilis: comparación de 2 inmunoensayos quimioluminiscentes con el Treponema pallidum hemagglutination assay / Contribution of automated serological tests in the diagnosis of syphilis: Comparison of 2 chemiluminescence immunoassays with Treponema pallidum hemagglutination assay

La aparición de pruebas treponémicas automatizadas ha conllevado un cambio en el algoritmo diagnóstico de la sífilis. Tras comparar el algoritmo automatizado con el tradicional, evaluamos 2 inmunoensayos quimioluminiscentes (CLIA). Sobre 94 sueros se realizó RPR, TPHA y la técnica Architect Syphil TP (STP). En una segunda fase en 100 muestras se comparó el STP frente a Immulite Syphilis screen (ISS). En la primera fase hubo un falso positivo del STP respecto a 8 del RPR. En la segunda fase hubo una diferencia de especificidad estadísticamente significativa a favor del ISS. El uso de CLIA disminuye los errores analíticos y el tiempo de personal técnico frente a las pruebas no treponémicas. Ambos CLIA son útiles como prueba de cribado (AU)

The introduction of automated treponemal chemiluminescence assay (CLIA) has led to a change in the diagnostic algorithm of syphilis. The objective of the work was to compare the traditional algorithm with the automated one and evaluating two CLIA assays. A total of 94 sera were tested for rapid plasma reagin (RPR), Treponema pallidum hemagglutination (TPHA) and Architect Syphil TP (Syphilis Treponema pallidum, STP). In a second phase, 100 samples were compared, STP against Immulite Syphilis screen (ISS). In the first phase, 8 false positive RPR were found with just 1 STP. In the second phase, a statistically significant difference was found in the specificity in favour of the ISS. The use of CLIA reduces analytical errors and staff time spent on the nontreponemal test. Both CLIA are useful as screening tests (AU)

Introduction of rapid tests for large-scale syphilis screening among female, male, and transgender sex workers in Mumbai, India.

BACKGROUND: Despite widespread availability of rapid plasma reagin (RPR) for syphilis screening at sex worker (SW)-dedicated project clinics, uptake of syphilis testing remains low and prevalence of syphilis remains high among SWs in Maharashtra, India. The primary reasons given for refusal of RPR were fear of venipuncture and long waiting times for results. METHODS: Between December 2007 and February 2008, rapid point of contact diagnostic tests (Syphicheck-WB, Qualpro Diagnostics, India) using finger-prick samples were introduced for syphilis screening, with RPR confirmation test of positives. RESULTS: Uptake of syphilis screening among clinic attenders increased to 63.1% compared with an average of 14.3% before the intervention. Among the 19,809 SWs who were screened, 598 tested positive (3% prevalence of lifetime infection). Of these, 395 (66.1%) accepted RPR confirmation test; 337 (88.3%) were seroreactive, 160 (40.5%) had titers ≥1:8 (active syphilis). The projected overall prevalence of active syphilis among all SWs screened was 1.2% but varied by site and typology of sex work (brothel-based, 2.4%; bar-based, 0.5%; street-based, 2.3%; male SWs, 0.2%; transgender, 11.3%; home-based, 0.6%). CONCLUSIONS: The introduction of rapid tests dramatically increased the uptake of syphilis screening in this large-scale intervention among a high-risk population in India. However, only two-thirds of SWs with a positive rapid test accepted a confirmatory RPR test. The high proportion (40.5%) of active syphilis among those testing positive on the rapid screening test justifies treatment even if confirmatory testing is declined. A commercially available, simple, rapid nontreponemal test is needed to further strengthen syphilis screening.

An immunofiltration device for the simultaneous detection of non-treponemal and treponemal antibodies in patients with syphilis.

OBJECTIVE: The development of a rapid immunofiltration (flow-through) test for the simultaneous detection of non-treponemal and treponemal antibodies in the serum of patients with syphilis. METHODS: The assay is rapid, inexpensive, and requires limited expertise in interpreting the results. The test is based on the principle of immunofiltration, with two antigens and control material spotted on the membrane of a through-flow device. A positive test is characterised by the appearance of three red/magenta spots within 2-10 min. RESULTS: A total of 376 banked serum samples obtained from the Georgia Public Health Laboratory was examined by the flow-through test, the rapid plasma reagin (RPR) test and the Treponema pallidum passive particle agglutination assay (TPPA). The sensitivity and specificity of the non-treponemal spot were 96.5% and 97.7%, respectively, when compared with the RPR test, and the sensitivity and specificity of the treponemal test spot were 97.3% and 99.1% when compared with the TPPA test. In addition, the test yielded equivalent results to those obtained in comparator tests when 104 sera from cases of syphilis of known stage, 49 sera from diseases other than syphilis and 23 sera known to exhibit biological false-positive reactions were tested in parallel. CONCLUSIONS: These results indicate that the dual treponemal and non-treponemal assay could be used as a screen and confirmatory test for the serological diagnosis of syphilis in remote or resource-poor settings where there is a need to provide counselling and treatment at the initial consultation.

[Comparative study of immunochromatographic sets for rapid diagnosis of syphilis].

The paper presents the results of the comparative study of 9 commercial kits made in foreign countries for the rapid diagnosis of syphilis, performed at the Central Research Institute of Dermatovenereological Infections, Russian Agency for Health Care, within the framework of the International Sexual Transmitted Diseases Diagnostic Initiative Program under the aegis of the World Health Organization during 2002-2005. The above diagnostic kits were assessed in the context of the availability of and statement simplicity in the instruction for use; the technological complexity in performing a study procedure and the simplicity in interpreting the findings; the necessity of employing additional laboratory equipment. The parameters of the clinical efficiency (sensitivity and specificity) were studied; a passive sensitized red blood cell agglutination test was used as a reference method. The comprehensive study showed that the "Determine Syphilis TP test system ("Abbot Lab", USA) yielded the best results with a total of 10 scores at 100% sensitivity and 100% sensitivity) while the "Bioline Syphilis anti-TP Test Card" ("Pacific Biotech Co.", Thailand) provided a total of 9 scores at 96% sensitivity and 98% specificity.

[A syphilis marker study of blood component donors]. / Issledovanie markerov sifilisa u donorov gemokomponentov.

Laboratory testing of donor blood is the key point in prevention of hemotransmissive syphilis. The probability of using diagnostic EIA kit RecombiBest antipallidum-strip (AO Vektor-Best, Novosibirsk) is assessed. Ninety-two donor sera were tested. For assessing the sensitivity of the test system, 11 sera of syphilis patients were titrated by double dilutions 1:10 to 1:1280 for each strip. In parallel with this, antibodies to T. pallidum were assessed in the precipitation microtest. EIA proved to be not only highly specific, but more sensitive than precipitation microtest. Antibodies to T. pallidum are detected by EIA in serum dilutions at least two times higher than the minimal titers in the precipitation test. Thus, the above diagnostic kit is recommended for screening of donors of blood and its components.