Performance of a Novel Human Immunodeficiency Virus (HIV) Type 1 Total Nucleic Acid-Based Real-Time PCR Assay Using Whole Blood and Dried Blood Spots for Diagnosis of HIV in Infants

Stevens, Wendy; Erasmus, Linda; Moloi, Matsidisho; Taleng, Thabo; Sarang, Somaya

doi:10.1128/jcm.00754-08

Cited by 62 publications

(65 citation statements)

References 24 publications

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“…The CAP/CTM is a total nucleic acid real-time reverse transcriptase PCR assay that detects HIV-1 proviral DNA and RNA on whole blood, and HIV-1 RNA only on plasma, with a limit of detection of approximately 300 RNA copies/ml and limit of quantification of 20 RNA copies/ml, respectively [11,28]. All non-negative virological results were interpreted according to standard criteria used within the National Health Laboratory Service (NHLS) to distinguish clearly positive from indeterminate results.…”

Section: Laboratory Methodsmentioning

confidence: 99%

Prevalence and outcomes of HIV‐1 diagnostic challenges during universal birth testing – an urban South African observational cohort

Technau

Mazanderani

Kuhn

et al. 2017

Journal of the International AIDS Society

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Introduction: HIV-1 polymerase chain reaction (PCR) testing at birth aims to facilitate earlier initiation of antiretroviral therapy (ART) for HIV-infected neonates. Data from two years of universal birth testing implementation in a high-burden South African urban setting are presented to demonstrate the prevalence and outcomes of diagnostic challenges in this context. Methods: HIV-exposed neonates born at Rahima Moosa Mother and Child Hospital between 5 June 2014 and 31 August 2016 were routinely screened at birth for HIV-1 on whole blood samples using the COBAS® AmpliPrep/COBAS® TaqMan (CAP/CTM) HIV-1 Qualitative Test, version 2.0 (Roche Molecular Systems, Inc., Branchburg, NJ, USA). Virological results were interpreted according to standard operating procedures with the South African National Health Laboratory Service. All neonates with non-negative results were actively followed-up and categorized according to HIV infection status as positive, negative, uncertain and lost to follow-up (LTFU). Results: 104 (1.8%) of 5743 HIV-exposed neonates received a non-negative birth PCR result, for which laboratory data were available for 102 (98%) cases – 78 (76%) tested positive and 24 (24%) indeterminate. HIV infection status was confirmed positive in 83 (81%) infants, negative in 8 (8%), uncertain in 5 (5%) and LTFU in 6 (6%) cases. The positive predictive value (excluding cases of uncertain diagnosis and inadequate testing) following a non-negative HIV-1 PCR screening test at birth was 0.91 (83/91; 95% confidence interval: 0.85–0.96). Neonates testing positive at birth had significantly higher viral load (VL) results than those testing indeterminate at birth of 4.5 and 3.0 log copies/ml (p = 0.0007), respectively. Similarly, mothers of neonates with positive as compared to indeterminate birth test results had higher VLs of 4.5 and 2.7 log copies/ml (p = 0.0013), respectively. Half of neonates with an indeterminate birth test were shown to be HIV-infected on subsequent confirmatory testing, with time to final diagnosis 30 days longer for these neonates (p < 0.0001). Conclusion: Indeterminate HIV-1 PCR results accounted for a quarter of non-negative results at birth and were associated with a high risk of infection in comparison to the risk of in utero transmission. Indeterminate birth results with positive HIV PCR results on repeat testing were associated with later final diagnosis. The HIV-1 status remains uncertain in a minority of cases because of repeatedly indeterminate results, highlighting the need for more sensitive and specific virological tests.

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Section: Laboratory Methodsmentioning

confidence: 99%

Prevalence and outcomes of HIV‐1 diagnostic challenges during universal birth testing – an urban South African observational cohort

Technau

Mazanderani

Kuhn

et al. 2017

Journal of the International AIDS Society

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“…The viral loads of HIV-infected infants may start out low at birth and increase over time (13). Therefore, a more sensitive HIV PCR test can lead to earlier, more accurate diagnosis (14), which can minimize the occurrence of We have demonstrated that the TaqMan HIV-1 Qual Test version v2.0 has increased sensitivity compared to the previously determined sensitivity for the v1.0 assay (15). The Probit 95% LOD for the v2.0 test is 16.5 cp/ml in plasma samples, compared to 514 cp/ml for the v1.0 test.…”

Section: Discussionmentioning

confidence: 89%

“…The previous test version required prelysis of plasma samples with SPEX buffer, limiting the effective sample input volume to Ͻ100 l (15). Since this step is no longer required, 850 l of sample volume can be used in the assay.…”

Section: Discussionmentioning

confidence: 99%

Improved Sensitivity of a Dual-Target HIV-1 Qualitative Test for Plasma and Dried Blood Spots

et al. 2016

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eThe use of nucleic acid detection for HIV type 1 (HIV-1) detection is strongly recommended in infants <18 months of age, in whom serology is unreliable. This study evaluated the Cobas AmpliPrep/Cobas TaqMan HIV-1 Qualitative Test v2.0 (TaqMan HIV-1 Qual Test, v2.0), a dual-target total nucleic acid real-time PCR assay. The limit of detection (LOD) of the new test in plasma and dried blood spots (DBS) was determined with the 2nd International HIV-1 RNA WHO standard. The specificity of the assay was tested with EDTA plasma (n ‫؍‬ 1,301) and DBS from HIV-negative adults (n ‫؍‬ 1,000). The sensitivity was determined using HIV-1-positive samples (n ‫؍‬ 169 adult EDTA plasma, n ‫؍‬ 172 adult DBS, and n ‫؍‬ 100 infant DBS) that included group M, subtypes A to H, CRF01_AE, CRF02_AG, and groups O and N. All positive specimens and a subset of the negative specimens were also tested with the Abbott RealTime HIV-1 Qual assay (RealTime). The LOD of the TaqMan assay was 20 copies/ml in plasma and 300 copies/ml in DBS, with specificities of 99.8% in plasma and 99.9% in DBS. The TaqMan . Although access to early infant diagnosis of HIV is improving, in 2011 only 35% of infants born to HIV-positive mothers were tested within 2 months of birth (1). The Joint United Nations Programme on HIV/AIDS (UNAIDS) call for action has set new targets for 2020, the first of which is for 90% of those infected with HIV to know their status. Improved assays like the one evaluated in this study should assist in increasing access to HIV diagnosis, particularly in a vulnerable pediatric population that requires nucleic acid-based testing (2). Transmission of HIV occurs through sexual contact, exposure to infected blood products (3), and vertical mother-to-child transmission (4). For many infected infants, the progression of AIDS is rapid, and thus, early antiretroviral therapy is crucial for survival. In a randomized, controlled clinical trial in South Africa, it was demonstrated that early HIV diagnosis and early antiretroviral therapy could reduce early infant mortality by 76% and slow HIV progression by 75% (5). Access to HIV testing and early confirmation of a pediatric infection are thus critical for immediate access to treatment and care programs. Nucleic acid testing is particularly important for early diagnosis of infants Յ18 months of age. In this population, serologic tests are unreliable for the identification of true virologic status, because passively transferred maternal HIV type 1 (HIV-1) antibodies may be detectable in the HIV-exposed infant for up to 18 months of life (6) or longer in some instances (7). Thus, the World Health Organization (WHO) strongly recommends that HIV virological testing be used to diagnose HIV infections in infants and children below 18 months of age (8). The regions that are most severely affected by the HIV epidemic, such as sub-Saharan Africa, are often faced with severe resource constraints limiting access to virological testing. The difficulties of cold-chain transfer of collected blood samples from ...

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“…Evaluation of the CAP/CTM assay using clinical specimens from HIV-exposed children in SA has revealed a limit of detection of 1 090 copies/ml and sensitivities of between 98.8% and 99.7%. [11,12] Criteria that define low-positive results as indeterminate have been adopted by all early infant diagnostic centres in SA, and are determined by a cycle threshold value of >33 and/or a fluorescence intensity value of <5 (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

Loss of detectability and indeterminate results: Challenges facing HIV infant diagnosis in South Africa’s expanding ART programme

et al. 2014

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Performance of a Novel Human Immunodeficiency Virus (HIV) Type 1 Total Nucleic Acid-Based Real-Time PCR Assay Using Whole Blood and Dried Blood Spots for Diagnosis of HIV in Infants

Cited by 62 publications

References 24 publications

Prevalence and outcomes of HIV‐1 diagnostic challenges during universal birth testing – an urban South African observational cohort

Prevalence and outcomes of HIV‐1 diagnostic challenges during universal birth testing – an urban South African observational cohort

Improved Sensitivity of a Dual-Target HIV-1 Qualitative Test for Plasma and Dried Blood Spots

Loss of detectability and indeterminate results: Challenges facing HIV infant diagnosis in South Africa’s expanding ART programme

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