Field evaluation of near point of care Cepheid GeneXpert HIV-1 Qual for early infant diagnosis

Abstract

BackgroundAccess to point-of-care HIV testing shortens turn-around times, time to diagnosis and reduces loss to follow-up hence minimizing barriers to early linkage to care and treatment among HIV infected infants. Currently samples for early infant HIV diagnosis are sent to centralized testing facilities which are few and located only at specific regions in Kenya. However, there are Point of Care (POC) early infant diagnosis [EID] technologies elsewhere such as SAMBA and ALERE-Q that are yet to be evaluated in Kenya despite the urgent need for data to inform policy formulation regarding EID. The Cepheid GeneXpert HIV-1 Qual (GeneXpert) technology for POC EID offers a great opportunity to minimize HIV associated morbidity, mortality and loss to follow-up through decentralization of early infant HIV testing to the clinics. This technology also allows for same-day results thus facilitating prompt linkage to care.MethodsWe evaluated the GeneXpert HIV Qual EID POC in Homabay County against the standard of care platform, Roche CAP/CTM HIV-1 qualitative PCR, using dried blood spots (DBS). Between February—July 2016, DBS samples were collected from HIV exposed children <18 months of age enrolled in a cross-sectional study. Samples were collected by qualified nurse counselors, and were tested by trained technicians using field based GeneXpert and conventional laboratory based Roche CAP/CTM HIV-1 qualitative PCR. Sensitivity and specificity were determined.ResultsOverall, 3,814 mother/infant pairs were included in the study, out of which 921 infants were HIV exposed as per the mothers’ HIV status and based on the infant’s HIV rapid test. A total of 969 PCR tests were performed, out of which 30 (3.3%) infants were concordantly positive using both platforms. GeneXpert HIV-1 Qual yielded a sensitivity of 94.1% and specificity of 99.8% with an overall error rate of 0.7%.ConclusionOur findings show that GeneXpert HIV-1 Qual performs well compared to CAP/CTM using DBS samples, suggesting that this technology may be adopted in decentralized laboratories as a near POC device. It may contribute to prompt diagnosis of HIV exposed infants hence enabling early linkage to care, thus advancing further gains in EID.

Point‐of‐care HIV maternal viral load and early infant diagnosis testing around time of delivery at tertiary obstetric units in South Africa: a prospective study of coverage, results return and turn‐around times

“…The proportions with POC EID error/invalid results in our study were higher than proportions of up to 9.3% reported in other studies [9,12,20‐21,24]. Among the EID error/invalid results, 50.2% were associated with cartridges belonging to three specific lots which may suggest faulty cartridges.…”

“…POC VL testing improves turn‐around time (TATs) and retention in care among adults on ART [8], while POC EID testing reduces TATs and time to ART initiation in infants [9‐14]. Both have potential to reduce morbidity and mortality among pregnant WLHIV and their infants.…”

“…Two POC VL and two POC EID assays have been prequalified by WHO. Cepheid’s Xpert HIV‐1 quantitative and HIV‐1 qualitative assay (Cepheid, Sunnyvale, CA, USA) [15,16], as well as Abbott’s m‐Pima HIV‐1/2 VL and q‐HIV‐1/2 Detect (Abbott, Chicago, IL, USA) [17,18], had comparable performance to standardized laboratory assays in multiple settings [9,12,19‐21]. However, there is limited data on routine scale up POC testing for WLHIV and their infants.…”

Programmatic evaluation of feasibility and efficiency of at birth and 6-week, point of care HIV testing in Kenyan infant

“…POC diagnostic technologies such as GeneXpert HIV-1 Qual [ 15 ] and Alere m-PIMA [ 16 ] are cartridge-based tests that can be processed at the hospital by trained clinical or laboratory staff and can result in more rapid turnaround times of results, more infants being identified as HIV-positive and more infants initiated on ART at younger ages than traditional testing strategies [ 17 – 22 ]. Studies have shown high sensitivity and specificity of POC testing and found that POC implementation is feasible in hospital-based settings in Kenya [ 23 , 24 ], South Africa [ 18 , 25 – 27 ], Mozambique [ 28 ], and Tanzania [ 29 ]; is acceptable to providers [ 26 ] and patients [ 30 ]; and may be a cost-effective option for EID [ 31 , 32 ]. Based on the promising evidence supporting POC, the World Health Organization (WHO) conditionally recommended the introduction of POC for EID in 2016 [ 33 ].…”

Microfluidic Point-of-Care Testing: Commercial Landscape and Future Directions

“…GeneXpert systems by Cepheid is a near POCT NAAT that relies on hemi-nested qualitative PCR. GeneXpert HIV-1 Qual and GeneXpert MTB/RIF panels are currently being used for early infant HIV diagnosis and MTB/Rifampicin detection (Saeed et al, 2017 ; Opollo et al, 2018 ). With the ongoing COVID-19 pandemic, Xpert Xpress SARS-Cov2 test by Cepheid was the first to be approved by FDA for coronavirus testing and can produce results in about 45 min (Opollo et al, 2018 ).…”