External quality assurance methods are feasible for syphilis and HIV point-of-care tests in antenatal clinics

The implementation of an external quality assurance method for point-of-care tests for HIV and syphilis in Tanzania.

Smit PW, Mabey D, van der Vlis T, Korporaal H, Mngara J, Changalucha J, Todd J, Peeling RW. BMC Infect Dis. 2013 Nov 9;13(1):530. [Epub ahead of print]

Background: External quality assurance (EQA) programmes, which are routinely used in laboratories, have not been widely implemented for point-of- care tests (POCTs). A study was performed in ten health centres in Tanzania, to implement the use of dried blood spots (DBS) as an EQA method for HIV and syphilis (POCTs).

Method: DBS samples were collected for retesting at a reference laboratory and the results compared to the POCT results obtained at the clinic. In total, 2 341 DBS samples were collected from 10 rural health facilities over a period of nine months, of which 92.5% were correctly collected and spotted.

Results: The EQA method was easily implemented by healthcare workers under routine conditions in Northern Tanzania. For HIV, 967 out of 972 samples (99.5%) were concordant between DBS and POCT results. For syphilis, the sensitivity of syphilis tests varied between clinics with a median of 96% (25th and 75th quartile; 95-98%). The specificity of syphilis POCT was consistent compared to laboratory based test using DBS, with a median of 96% (25th and 75th quartiles; 95-98%).

Conclusion: Overall, the quality of testing varied at clinics and EQA results can be used to identify clinics where healthcare workers require remedial training, suggesting the necessity for stringent quality assurance programmes for POC testing. As Tanzania embarks on scaling up HIV and syphilis testing, DBS can be a useful and robust tool to monitor the quality of testing performed by healthcare workers and trigger corrective action to ensure accuracy of test results.

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Editor’s notes:  This is the first study to demonstrate that dried blood spots may be used as an external quality assurance method for syphilis and HIV point-of-care tests in antenatal clinics (ANC).  Ten clinics were evaluated, and the quality varied, indicating that the external quality assurance (EQA) results can be used to identify clinics where remedial training is required.  Notably, the results from a syphilis proficiency panel of known positive and negative sera did not correlate well with results from the EQA. The study also shows that it is possible to integrate HIV and syphilis quality assurance for point-of-care tests.

Epidemiology, HIV testing
United Republic of Tanzania
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