Evaluation of the Elecsys syphilis immunoassay for routine screening of serum samples in China

A study of performance evaluation of cobas e 801 infectious diseases panel

BACKGROUND

Infectious diseases, such as HCV infection, HBV infection and syphilis, put a huge burden on public health. Accurate and fast testing is required for clinical usage.

OBJECTIVES

This study aimed to evaluate the clinical performance of Elecsys® Anti-HCV II, Elecsys® HBsAg II and Elecsys® Syphilis using samples from routine diagnosis in China.

METHODS

Specificity was tested in approximately 3000 unselected pseudonymized samples from routine clinical patients for each assay. Sensitivity of HCV and HBsAg assays was tested in 2 seroconversion panels, respectively.

RESULTS

The 3 investigational assays on cobas e 801 were showed to have excellent sensitivity and specificity which is comparable to existing assays.

CONCLUSION

They are suitable for routine clinical diagnostic use, including pre-operative assessment in China.

Comparison and evaluation of Abbott chemiluminescent microparticle immunoassay and ChIVD light-initiated chemiluminescent assay in the detection of Treponema pallidum antibody

Background

Laboratory tests play an important role in the diagnosis of syphilis. This study aimed to compare and assess the performance of the Abbott chemiluminescent microparticle immunoassay (CMIA) and the ChIVD light‐initiated chemiluminescent assay (LICA) in the detection of Treponema pallidum (TP) antibody.

Methods

A total of 10 498 serum samples were detected with two assays, and the Treponema pallidum particle agglutination assay (TPPA) and recombinant immunoblot assay (RIBA) methods were used for confirmation. The sensitivity, specificity, positive predictive value, and negative predictive value of the Abbott CMIA and ChIVD LICA were calculated. The coincidence rate between two assays was also evaluated. The causes of false positive and false negative of two assays were studied.

Results

For the Abbott CMIA and ChIVD LICA, the sensitivity was 94.44% and 98.15%, the specificity was 99.89% and 99.81%, the positive predictive value was 93.29% and 88.83%, and the negative predictive value was 99.91% and 99.97%, respectively. The coincidence rate between Abbott CMIA and ChIVD LICA was 99.26%, and κ value was .790. The disease of infertility, hypertensive disease, liver disease, and cancer were the common causes of false positive in both assays, while infertility was also the main reason lead to false negative.

Conclusion

Our results demonstrated that the Abbott CMIA and ChIVD LICA generally had high sensitivity and specificity and therefore may be suitable for the detection of TP antibody and screening for syphilis.

Neurosyphilis cerebrospinal fluid findings in patients with ocular syphilis

Purpose: To evaluate neurosyphilis cerebrospinal fluid (CSF) findings and initial ophthalmic manifestations in patients with syphilitic uveitis.Methods: We retrospectively reviewed the records of CSF analysis of 14 patients with syphilitic uveitis with treponemal analysis - chemiluminescent immunoassay and TPHA- and non-treponemal analysis - Rapid Plasma Reagin test - RPR.Results: 86% were males and 43% HIV+. Ocular signs of syphilis lead to the diagnosis of syphilis in 78% of patients. Typical syphilitic uveitis presentations included: acute syphilitic posterior placoid chorioretinitis (50% of patients), retinitis (21% of patients) and punctate inner retinitis (7% of patients). 57% of patients had definite neurosyphilis by the CDC criteria, while 71% had CSF abnormalities suggestive of central nervous system involvement.Conclusion: Based on international guidelines, the frequent CSF abnormalities found in syphilitic uveitis patient supports the diagnosis of neurosyphilis in a majority of patients.

Evaluation of ELISA and CLIA for Treponema pallidum specific antibody detection in China: A multicenter study

BACKGROUND

Considering the rapid increase of syphilis infections in several countries including China, searching for a screening test with sufficient sensitivity and specificity is extremely urgent. The current study mainly researched the performance for Treponema pallidum (TP) detection by electro-chemiluminescence immunoassays (ECLIA), chemiluminescence immunoassays (CLIA) and four commercially available ELISA assays commonly used in China.

METHODS

1372 plasma samples collected from blood centers/banks were tested with 6 assays in 8 laboratories with the Western blot (WB) or TP particle agglutination assay (TPPA) as confirmatory tests.

RESULTS

With the WB or TPPA as confirmatory test, the ECLIA demonstrated the highest specificity (95.2%) and Kappa coefficient (0.915), but lowest sensitivity (97.2%) compared with the other 5 assays. While the Wantai-ELISA showed the highest sensitivity (99.6%) among the 6 assays. Sensitivities were found to be significantly increased when any two of the six assays were combined for TP detection. Our study demonstrated that the Wantai-ELISA combined with the ECLIA or the KHB-ELISA or the InTec-ELISA would increase the sensitivities up to 100%. Further analysis showed that the specificities and positive predictive values were both 100.0% when cut-off of S/CO values were served as 15.42 for the ECLIA and 7.14 for the CLIA, indicating that samples under these conditions can be directly considered as positive without confirmation.

CONCLUSIONS

The CLIA and the ECLIA are more specific than ELISA to detect TP antibodies. However, ELISA is a sensitive method, especially in combination with the CLIA or the ECLIA or another types of ELISA, suitable for the routine screening of blood donations in China.

Comparison of Roche Elecsys and Sysmex HISCL immunoassays for the screening of common blood-borne pathogens

Background

We conducted a comprehensive comparison in the sensitivity, specificity, dilution sensitivity, and precision between two immunoassay systems, Roche Elecsys Cobas e 601 and Sysmex HISCL 5000, for the detection of hepatitis B virus surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), treponemal antibodies (anti-TP), and human immunodeficiency virus (HIV).

Methods

One thousand unselected samples and 100 reserved weak reactive samples were tested by the two systems. Sensitivity and specificity were then calculated for each system. Seroconversion panels were used to assess the sensitivity in early stage detection. Dilution sensitivity was evaluated by dilution tests of several seroconversion panel samples. Evaluation of within-run and intermediate precision was conducted following EP-15A protocol.

Results

The consistency rates of the two systems for the detection of four pathogens were all over 99% among unselected samples. Both Elecsys and HISCL were observed to have high sensitivity and specificity in unselected samples and weak reactive samples. Seroconversion panel tests showed that Elecsys could identify positive results earlier than HISCL in HBsAg (1 out of 4), anti-TP (1 out of 2) and HIV (1 out of 12) panels. The results of the anti-HCV panels were comparable. In dilution tests, Elecsys could detect lower concentrations than HISCL in two anti-HCV samples and one anti-TP sample. The two systems had similar performance in dilution tests of HBsAg and HIV samples. Both Elecsys and HISCL had qualified intra-assay and inter-assay precision.

Conclusions

Both Elecsys and HISCL have good performance in the screening of four common bloodborne pathogens. The two systems are comparable and considered adequate for clinical use.

Performance evaluation of nine different syphilis serological tests in comparison with the FTA-abs test

BACKGROUND

Serological methods have great importance for the detection of Treponema pallidum antibodies in syphilis diagnosis. The goal of the present study is to evaluate various commercially available screening assays in comparison with the FTA-abs test.

METHODS

A total of 363 serum samples were enrolled in the study. Following routine testing including RPR and TPHA tests, each sample was tested by treponemal immunoassays (Chorus Syphilis Screen Recombinant, Architect Syphilis TP, Syphilis Virclia Monotest, Siemens Advia Centaur Syphilis, Euroimmun Treponema pallidum Screen ELISA, Vircell Syphilis ELISA IgG + IgM, SD Bioline Syphilis). The result obtained from each test was compared with the confirmatory FTA-abs test. Kappa (κ) coefficients were used to compare the concordance of the tests.

RESULTS

When the various tests were evaluated in comparison with the FTA-abs test, the sensitivity, specificity and percent agreement of each test were as follows: Architect Syphilis TP, 92.3%, 94.5%, 92.8%; Chorus Syphilis Screen Recombinant, 87.9%, 91.2%, 88.7%; Syphilis Virclia Monotest, 80.5%, 97.8%, 84.9%; Siemens Advia Centaur Syphilis, 87.5%, 89%, 87.9%; Euroimmun Treponema pallidum Screen ELISA, 87.5%, 85.7%, 87.1%; Vircell Syphilis ELISA IgG + IgM, 73.2%, 62.6%, 70.5%; TPHA, 89%, 63.7%, 82.6%; SD Bioline Syphilis, 58.1%, 94.5%, 67.2%; RPR test, 57.7%, 57.1%, 57.6%.

CONCLUSION

The results of the present study show that Treponema pallidum specific immunoassays with a performance similar or better than TPHA test generally performed well with the confirmatory FTA-abs test and may be an alternative for screening total antibodies in syphilis infection.