Objectives This is a comparative review between using dried blood spot (DBS) and mini-tube (MT) HIV sampling kits as part of an online sexually transmitted infection (STI) postal testing service. England has recently seen increases in internet-based and postal (eHealth) STI services. Expanding accessibility and testing for patients, cost implications and narrowing the HIV undiagnosed margin are drivers for this.
Methods In 2017, data were reviewed from an online postal STI kit requesting service at a time of transitioning from MT to DBS. We compared the STI postal kit and HIV blood sample return rates, and the successful processing/analysis rates of the DBS and MT kits. Descriptive statistics were applied to participant characteristics, with Pearson’s χ2 or Fisher exact test used to demonstrate statistical differences. We also describe and calculate a ‘request-to-result ratio’ (RRR) for both kit types. The RRR is defined as the number of online kit requests required to produce one successfully analysed result.
Results 550 STI postal kit requests from a North-West of England region were reviewed from 13 June 2017 to 22 September 2017 (275 MT, 275 DBS). Baseline characteristics between the two groups were comparable (63% woman, 90% white British and 86% heterosexual with a median age of 26 years). The successful processing rate for the DBS was 98.8% c.f. 55.7% for the MT (p<0.001). The RRR for MT was 2.96, c.f. 1.70 for DBS. There was a 5.4% false positive HIV rate in the MT c.f. none in the DBS.
Conclusions This comparative analysis suggests that in this community setting, the use of postal HIV DBS kits resulted in a significantly improved RRR compared with MT. The biggest factor was the large number of MT samples not analysed due to inadequate blood volumes. The unexpected level of false positive results in the MT samples needs confirming in larger studies.
- laboratory methods
- genitourinary medicine services
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Handling editor Jackie A Cassell
Contributors MP, ST, DH, SW: drafted the manuscript. MS, DH and ST: co-developed the Saving Lives postal testing system, extracted the data and ensured good clinical governance throughout the data extraction process. MP, ST and MW: performed the statistical analysis. SFA, ES, SW and CA: developed and validated the HIV DBS testing system for PHE Birmingham described in this manuscript. All authors contributed to intellectual discussions and amendments to the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests ST is the unpaid Medical Director of the Saving Lives charity which provides the postal testing systems described in this manuscript. DH is the Director of operations for the Saving Lives charity which provides the postal testing systems described in this manuscript. MS is the head developer of the Saving Lives IT digital systems used in the postal testing systems described in this manuscript. SFA, ES, SW and CA are employees of Public Health England Laboratories Birmingham.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All available data can be obtained by contacting the corresponding author.
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