Separation of Plasma from Whole Blood by Use of the cobas Plasma Separation Card: a Compelling Alternative to Dried Blood Spots for Quantification of HIV-1 Viral Load

Carmona, Sergio; Seiverth, Britta; Magubane, Dieketseng; Hans, Lucia; Hoppler, Matthias

doi:10.1128/jcm.01336-18

Cited by 41 publications

(66 citation statements)

References 31 publications

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“…These cards maintain all the comparative advantages of DBS, while providing plasma as a matrix for laboratory assays. A recent study under controlled conditions in South Africa showed that viral load results determined using PSC correlated well with those generated using plasma [15]. Our study aimed at evaluating the performance of the PSC for HIV-1 viral load testing in patients…”

Section: Introductionmentioning

confidence: 88%

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Accurate HIV viral load measurement in primary health care settings using the cobas® plasma separation card

et al. 2020

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Introduction Plasma is considered the gold standard for HIV viral load (VL) testing, however its use is challenging due to the need for phlebotomy and centrifugation services, as well as cold chain for transporting to laboratories for testing. The use of Dried Blood Spot (DBS) specimen has allowed a rapid expansion of antiretroviral therapy (ART) monitoring in remote areas in many African countries, however, the VL in DBS may overestimate the copies of viral RNA result at the clinically relevant range of 1000 copies/ml, due to proviral DNA and intracellular RNA. The characteristics of the cobas ® Plasma Separation Card (PSC) specimen are similar to fresh plasma (gold standard), so a better performance of HIV VL is expetected in PSC specimen and can be an alternative to DBS. This study aims to evaluate the performance of cobas ® PSC for VL testing at primary health care facilities in Mozambique. Methodology HIV-1 infected adults on ART were enrolled consecutively in two health facilities in Mozambique, between August 2018 and October 2018. Capillary and venous cobas ® PSC, DBS and fresh plasma specimens were collected from each patient. All specimens were tested for VL using CAP/CTM v2.0. Sensitivity and specificity of viral load using DBS, capillary and venous PSC specimens were estimated. Viral load obtained in fresh plasma specimen was used as reference and a threshold of 1000 copies/ml was considered for the analyses. Results From the total 613 patients included for the study, 2444 specimens including DBS (613), plasma (613), venous cobas ® PSC (609) and capillary cobas ® PSC (609) were collected and 2407 results were obtained. Sensitivity and specificity of the VL using venous cobas ® PSC specimen at 1000 copies/ml threshold were 99.8% and 98.1% respectively, whereas for capillary cobas ® PSC sensitivity was 99.6% and specificity was 97.2%. For DBS VL, sensitivity was 96.9% and specificity was 81.8%. Misclassification rate was more prominent in DBS

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Section: Introductionmentioning

confidence: 88%

“…After drying the specimen on the card, it can be transported under a wide range of environmental conditions to a central testing laboratory. Detailed description of how PSC works is available in a recent publication of Carmona et al (2019).…”

Section: Specimen Collectionmentioning

confidence: 99%

Accurate HIV viral load measurement in primary health care settings using the cobas® plasma separation card

et al. 2020

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“…It is possible that the use of ELISA assays may have caused a systematic bias, as both ELISA assays showed imprecision with higher levels of CRP. Another potential source of error with DBS samples is changes in haematocrit due to inaccurate volume correction estimates, though dried plasma solutions may mitigate against this [29][30][31]. It is also likely that using the patient's subjective 'self-report' of are will not always distinguish an in ammatory are from an increase of pain due to other causes.…”

Section: Limitationsmentioning

confidence: 99%

Assessment of a dried blood spot C-reactive protein method to identify disease flares in rheumatoid arthritis patients

D’Cruz

McEleney

Cochrane

et al. 2020

Preprint

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Background Rheumatoid arthritis (RA) is characterised by painful, stiff and swollen joints. RA features sporadic ‘flares’ or inflammatory episodes – mostly occurring outside clinics - where symptoms worsen and plasma C-reactive protein (CRP) becomes elevated. Poor control of inflammation results in higher rates of irreversible joint damage, increased disability, and poorer quality of life. Flares need to be accurately identified and managed. A method comparison study was designed to assess agreement between CRP values obtained by dried blood spot (DBS) versus conventional venepuncture sampling. The ability of a weekly DBS sampling and CRP test regime to detect flare outside the clinic was also assessed. Methods Matched venepuncture and finger lancet DBS samples were collected from n=100 RA patients with active disease at baseline and 6 weeks (NCT02809547). A subset of n=30 RA patients submitted weekly DBS samples over the study period. Patient demographics, including self-reported flares were recorded. DBS sample CRP measurements were made by enzyme-linked immunosorbent assay, and venepuncture samples by a reference immunoturbometric assay. Data was compared between sample types by Bland-Altman and weighted Deming regression analyses. Flare detection sensitivity and specificity were compared between ‘minimal’ baseline and 6 week sample CRP data and the ‘continuous’ weekly CRP data. Results Baseline DBS ELISA assay CRP measures yielded a mean positive bias of 2.693 ± 8.640 (95% limits of agreement -14.24% to 19.63%), when compared to reference assay data. Deming regression revealed good agreement between the DBS ELISA method and reference assay data, with baseline data slope of 0.978 and intercept -0.153. The specificity of ‘continuous’ area under the curve (AUC) CRP data (72.7%) to identify flares, was greater than ‘minimal’ AUC CRP data (54.5%). Conclusions This study indicates reasonable agreement between DBS and the reference method, especially at low to mid-range CRP values. Importantly, longitudinal CRP measurement in RA patients helps to clearly identify flare and thus could assist in remote monitoring strategies and may facilitate timely therapeutic intervention.

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“…However, these are more difficult to obtain and prepare on‐site and negate several of the advantages of dried blood spots. An elegant solution could be the plasma separation card which separates plasma and cells from finger or heel prick blood collected by a capillary tube and then blotted onto the card, without the need for centrifugation …”

Section: Pre‐analytic Factors and The “Wrong” Nucleic Acidmentioning

confidence: 99%

Lessons in diagnostic virology: expected and unexpected sources of error

Zyl

Maritz

Newman

et al. 2019

Reviews in Medical Virology

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Viral diagnostics have shown continued innovation, with serological and molecular diagnostic assays pushing the limits of sensitivity. Technology has provided new automated shared diagnostic platforms that reduce hands-on time, while with globalisation of the diagnostic market, commercial assays are applied across epidemiologically diverse settings on different patient and viral populations. However, with these novel developments, new and often unexpected sources of diagnostic error emerge. In this review we will reflect on case studies that highlight these often underappreciated or unexpected diagnostic errors spanning pre-analytical, analytical, and post-analytic processes. We will also suggest approaches that could help identify error and reduce the impact on patient management.

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Separation of Plasma from Whole Blood by Use of the cobas Plasma Separation Card: a Compelling Alternative to Dried Blood Spots for Quantification of HIV-1 Viral Load

Cited by 41 publications

References 31 publications

Accurate HIV viral load measurement in primary health care settings using the cobas® plasma separation card

Accurate HIV viral load measurement in primary health care settings using the cobas® plasma separation card

Assessment of a dried blood spot C-reactive protein method to identify disease flares in rheumatoid arthritis patients

Lessons in diagnostic virology: expected and unexpected sources of error

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