Performance characteristics of an instrument-free point-of-care CD4 test (VISITECT®CD4) for use in resource-limited settings

Objective CD4+ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECT®CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/μL. This study aimed to evaluate VISITECT®CD4 test's diagnostic accuracy. Methods Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECT®CD4 tests. An additional finger-prick blood sample was obtained for VISITECT®CD4. VISITECT®CD4's diagnostic performance in identifying individuals with CD4 counts ≤350 cells/μL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference. Results The overall agreement between VISITECT®CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECT®CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using finger-prick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)]. Conclusion VISITECT®CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings.

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Non-invasive hemoglobin measurement devices require refinement to match diagnostic performance with their high level of usability and acceptability

PLoS ONE ◽

10.1371/journal.pone.0254629 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254629

Author(s):

Melissa F. Young ◽

Kelley Raines ◽

Farhad Jameel ◽

Manal Sidi ◽

Shaiana Oliveira-Streiff ◽

...

Keyword(s):

Clinical Performance ◽

Point Of Care ◽

Venous Blood ◽

Smartphone Application ◽

Multiple Point ◽

Structured Interviews ◽

Resource Limited ◽

User Acceptability ◽

High Level ◽

Sensitivity Specificity

Anemia remains an important global health problem. Inexpensive, accurate, and noninvasive solutions are needed to monitor and evaluate anemia in resource-limited settings. We evaluated the performance of multiple point-of-care hemoglobin devices, including a novel noninvasive smartphone application tested on Apple® and Android® cell phones, Masimo Pronto®, and HemoCue® Hb-301 and Hb-801, against a gold-standard hematology analyzer (reference hemoglobin) using venous blood. We examined correlations between hemoglobin devices and reference hemoglobin, device accuracy (average bias, Bland-Altman plots, clinical performance) and classification bias (sensitivity, specificity) among 299 refugees (10mo-65y) in Atlanta, GA. Semi-structured interviews (n = 19) with participants and staff assessed usability and acceptability. Mean reference hemoglobin was 13.7 g/dL (SD:1.8) with 12.5% anemia. Noninvasive hemoglobin devices were not well correlated with reference hemoglobin (Apple® R2 = 0.08, Android® R2 = 0.11, Masimo Pronto® R2 = 0.29), but stronger correlations were reported with HemoCue® Hb-301 (R2 = 0.87) and Hb-801 (R2 = 0.88). Bias (SD) varied across each device: Apple®: -1.6 g/dL (2.0), Android®: -0.7 g/dL (2.0), Masimo Pronto®: -0.4 g/dL (1.6), HemoCue® Hb-301: +0.4 g/dL (0.7) and HemoCue® Hb-801: +0.2 g/dL (0.6). Clinically acceptable performance (within ± 1 g/dL of reference hemoglobin) was higher for the invasive devices (HemoCue® Hb-301: 90.3%; HemoCue® Hb-801: 93.4%) compared to noninvasive devices (Apple®: 31.5%; Android®: 34.6%; Masimo Pronto®: 49.5%). Sensitivity and specificity were 63.9% and 48.2% for Apple®, 36.1% and 67.6% for Android®, 45.7% and 85.3% for Masimo Pronto®, 54.3% and 97.6% for HemoCue® Hb-301, and 66.7% and 97.6% for HemoCue® Hb-801. Noninvasive devices were considered easy to use and were the preferred method by participants. Among the only studies to compare multiple point-of-care approaches to hemoglobin testing, the diagnostic ability of HemoCue® was comparable to reference hemoglobin, while noninvasive devices had high user acceptability but considerable biases. Improvements in noninvasive device performance and further testing in anemic populations are recommended before broader use.

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Evaluation of the Alere Pima™ for CD4+ T lymphocytes counts in HIV-positive outpatients in Southern Brazil

International Journal of STD & AIDS ◽

10.1177/0956462414526862 ◽

2014 ◽

Vol 25 (13) ◽

pp. 956-959 ◽

Cited By ~ 9

Author(s):

L Rathunde ◽

GMB Kussen ◽

MP Beltrame ◽

LM Dalla Costa ◽

SM Raboni

Keyword(s):

Flow Cytometry ◽

T Lymphocytes ◽

T Lymphocyte ◽

Predictive Value ◽

Opportunistic Infections ◽

Point Of Care ◽

High Sensitivity ◽

Hiv Positive ◽

Point Of Care Test ◽

Patients At Risk

CD4 + lymphocyte counts are routinely ordered during the early phases of antiretroviral therapy and for prophylaxis of opportunistic infections in HIV-positive patients. Flow cytometry is the standard methodology for CD4 counts in Brazilian reference laboratories. However, these laboratories are located in large cities, frequently distant from patients, thus limiting patient access and delaying results. We compared a point-of-care test with flow cytometry determination of CD4+ T lymphocyte counts in HIV patients. We analysed 107 consecutive samples by both methods. Overall, the point-of-care test performed well, with excellent agreement between it and the standard method. Test results were concordant for patients with CD4+ T lymphocyte values above and below 200 cells/mm 3. The performance characteristics obtained were sensitivity 94% (95% CI 89.5–98.5%), specificity 93% (95% CI 88.2–97.8%), positive predictive value 86% (95% CI 79.4–92.6%), and negative predictive value 97% (95% CI 94–100%). The high sensitivity and specificity of the point-of-care test methodology suggest its utility as an alternative method for rapid measurement of CD4+ T lymphocytes in patients with limited access to reference laboratories, enabling prompt therapeutic intervention for patients at risk of progression to AIDS.

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Field Performance and Diagnostic Accuracy of a Low-Cost Instrument-Free Point-of-Care CD4 Test (Visitect CD4) Performed by Different Health Worker Cadres among Pregnant Women

Journal of Clinical Microbiology ◽

10.1128/jcm.01277-18 ◽

2018 ◽

Vol 57 (2) ◽

Cited By ~ 4

Author(s):

Stanley Luchters ◽

Karl Technau ◽

Yasmin Mohamed ◽

Matthew F. Chersich ◽

Paul A. Agius ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Pregnant Women ◽

Health Worker ◽

Rural Areas ◽

Point Of Care ◽

Low Cost ◽

Venous Blood ◽

Field Performance ◽

Hiv Care ◽

Finger Prick

ABSTRACT Measuring CD4 counts remains an important component of HIV care. The Visitect CD4 is the first instrument-free low-cost point-of-care CD4 test with results interpreted visually after 40 min, providing a result of ≥350 CD4 cells/mm3. The field performance and diagnostic accuracy of the test was assessed among HIV-infected pregnant women in South Africa. A nurse performed testing at the point-of-care using both venous and finger-prick blood, and a counselor and laboratory staff tested venous blood in the clinic laboratory (four Visitect CD4 tests/participant). Performance was compared to the mean CD4 count from duplicate flow cytometry tests on venous blood (FACSCalibur Trucount). In 2017, 156 patients were enrolled, providing a total of 624 Visitect CD4 tests (468 venous and 156 finger-prick samples). Of 624 tests, 28 (4.5%) were inconclusive. Generalized linear mixed modeling showed better performance of the test on venous blood (sensitivity = 81.7%; 95% confidence interval [CI] = 72.3 to 91.1]; specificity = 82.6%, 95% CI = 77.1 to 88.1) than on finger-prick specimens (sensitivity = 60.7%; 95% CI = 45.0 to 76.3; specificity = 89.5%, 95% CI = 83.2 to 95.8; P = 0.001). No difference in performance was detected by cadre of health worker (P = 0.113) or between point-of-care versus laboratory-based testing (P = 0.108). Adequate performance of Visitect CD4 with different operators and at the point of care, with no need of electricity or instrument, shows the potential utility of this device, especially for facilitating decentralization of CD4 testing services in rural areas.

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Validation of a point-of-care rapid diagnostic test for hepatitis C for use in resource-limited settings

International Health ◽

10.1093/inthealth/ihy101 ◽

2019 ◽

Vol 11 (4) ◽

pp. 314-315

Author(s):

James S Leathers ◽

Maria Belen Pisano ◽

Viviana Re ◽

Gertine van Oord ◽

Amir Sultan ◽

...

Keyword(s):

Point Of Care ◽

Low Cost ◽

Rapid Diagnosis ◽

Direct Acting Antivirals ◽

Resource Limited Settings ◽

Rapid Diagnosis Test ◽

Resource Limited ◽

Specificity And Sensitivity ◽

Hcv Screening ◽

Direct Acting

Abstract Background Treatment of HCV with direct-acting antivirals has enabled the discussion of HCV eradication worldwide. Envisioning this aim requires implementation of mass screening in resource-limited areas, usually constrained by testing costs. Methods We validated a low-cost, rapid diagnosis test (RDT) for HCV in three different continents in 141 individuals. Results The HCV RDT showed 100% specificity and sensitivity across different samples regardless of genotype or viral load (in samples with such information, 90%). Conclusions The HCV test validated in this study can allow for HCV screening in areas of need when properly used.

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COVID-19 Seroprevalence among Healthcare Workers of a Large COVID-19 Hospital in Rome Reveals Strengths and Limits of Two Different Serological Tests

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052650 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2650

Author(s):

Giuseppe Vetrugno ◽

Daniele Ignazio La Milia ◽

Floriana D’Ambrosio ◽

Marcello Di Pumpo ◽

Roberta Pastorino ◽

...

Keyword(s):

Blood Test ◽

Healthcare Workers ◽

Point Of Care ◽

Venous Blood ◽

Administrative Staff ◽

Serological Tests ◽

Predictive Values ◽

Work From Home ◽

Significant Difference ◽

Sensitivity Specificity

Healthcare workers are at the forefront against COVID-19, worldwide. Since Fondazione Policlinico Universitario A. Gemelli (FPG) IRCCS was enlisted as a COVID-19 hospital, the healthcare workers deployed to COVID-19 wards were separated from those with limited/no exposure, whereas the administrative staff were designated to work from home. Between 4 June and 3 July 2020, an investigation was conducted to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (IgG) antibodies among the employees of the FPG using point-of-care (POC) and venous blood tests. Sensitivity, specificity, and predictive values were determined with reverse-transcription polymerase chain reaction on nasal/oropharyngeal swabs as the diagnostic gold standard. The participants enrolled amounted to 4777. Seroprevalence was 3.66% using the POC test and 1.19% using the venous blood test, with a significant difference (p < 0.05). The POC test sensitivity and specificity were, respectively, 63.64% (95% confidence interval (CI): 62.20% to 65.04%) and 96.64% (95% CI: 96.05% to 97.13%), while those of the venous blood test were, respectively, 78.79% (95% CI: 77.58% to 79.94%) and 99.36% (95% CI: 99.07% to 99.55%). Among the low-risk populations, the POC test’s predictive values were 58.33% (positive) and 98.23% (negative), whereas those of the venous blood test were 92.86% (positive) and 98.53% (negative). According to our study, these serological tests cannot be a valid alternative to diagnose COVID-19 infection in progress.

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Prevalence and predictors of dyslipidemia on HAART and HAART naive HIV positive clients attending Debre Tabor Hospital, Debre Tabor, Ethiopia

10.21203/rs.3.rs-344322/v1 ◽

2021 ◽

Author(s):

Anemut Tilahun Mulu ◽

Getachew Yideg Yitbarek ◽

Fitalew Tadele Admasu ◽

Chalachew Yenew Denekew ◽

Biruk Demissie Melese

Keyword(s):

Venous Blood ◽

Cross Sectional Study ◽

Mean Value ◽

Anthropometric Measurement ◽

Hiv Positive ◽

Cross Sectional ◽

Immunodeficiency Virus ◽

Debre Tabor ◽

The Mean ◽

Cd4 Cell

Abstract Background: HAART has been reported to be associated with a number of side effects in human immunodeficiency virus patients among which dyslipidemia is a common metabolic disorder. Methods: A facility based comparative cross-sectional study among 228 HIV positive persons was conducted from July to August 2020. Socio-demographic and clinical data were collected using structured questionnaires. Fasting venous blood sample was drawn for Lipid profiles and CD4 cell determination. Anthropometric measurement was done. Data was analyzed using SPSS version 22 for windows. Result: A total of 228 HIV patients were enrolled in the study. Prevalence of dyslipidemia in HAART naive and on HAART HIV positive persons was 61(53.5%) and 84 (73.7%), respectively. The prevalence of TC≥200 mg/dl was 50% and 30%; HLD-c<40 mg/dl was 43.8% and 36%; LDL-c≥130mg/dl was 48.3% and 28.1%; and TG≥150 mg/dl 59.6% and 39% among on HAART and HAART naïve, respectively. Age greater than 40 years (AOR = 3.27, 95% C.I: 1.47 - 7.25), blood pressure ≥ 140/90 (AOR = 16.13, 95% C.I: 5.81 - 44.75), being on HAART (AOR = 2.73, 95 % C.I: 1.35 - 5.53) and body mass index > 25kg/m2 (AOR = 1.92, 95 % C.I: 1.20 - 4.81) were identified as determinants of dyslipidemia. Conclusion: The mean value of lipid profile was significantly higher among HIV positive clients on HAART as compared to those HAART naïve HIV positive clients.

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Use of a Sentinel Lymph Node Biopsy Algorithm in a South African Population of Patients With Cervical Cancer and High Prevalence of Human Immunodeficiency Virus Infection

International Journal of Gynecological Cancer ◽

10.1097/igc.0000000000001310 ◽

2018 ◽

Vol 28 (7) ◽

pp. 1432-1437 ◽

Cited By ~ 1

Author(s):

Leon Cornelius Snyman ◽

Emma P. Bryant ◽

Elize I. Wethmar ◽

Tom de Greve ◽

Florette Reyneke ◽

...

Keyword(s):

Cervical Cancer ◽

Human Immunodeficiency Virus ◽

Lymph Node ◽

Sentinel Lymph Node ◽

Positive Predictive Value ◽

Predictive Value ◽

Detection Rate ◽

Immunodeficiency Virus ◽

High Prevalence ◽

Sensitivity Specificity

ObjectivesCervical cancer is common in resource-poor settings with high prevalence of tuberculosis, pelvic inflammatory disease, and human immunodeficiency virus (HIV) infection. There are no data regarding the sentinel lymph node (SLN) algorithm in these high-risk cancer populations. Our objectives were to establish the sensitivity, specificity, positive predictive value, and negative predictive value of the SLN algorithm in cervical cancer and to compare the detection rate of indocyanine green (ICG) versus blue dye versus technetium Tc 99m nanocolloid (99mTc).MethodsThis prospective study was conducted at the University of Pretoria. 99mTc-nanocolloid tracer, ICG dye, and methylene blue (MB) were used to detect SLNs. Pathological ultrastaging was performed on hematoxylin-eosin– negative nodes.ResultsResults of 72 women were analyzed. The mean age was 47.2 years, 5.5% had a history of tuberculosis, 18.1% had pelvic inflammatory disease, and 65.3% were HIV positive. The SLN detection rate was 65.3%. Detection rate of MB was 56.9%; 99mTc, 69.4%; ICG, 87.5%; and the combination of MB and 99mTc, 91.7%. Pelvic nodal metastases occurred in 26.4%. The sensitivity, specificity, negative predictive value, and positive predictive value of SLN biopsy were 85.7%, 100%, 100%, and 98.33%, respectively. The false-negative rate was 14.3%, and it was 0% if the algorithm was applied.ConclusionsThe SLN algorithm is a feasible option for use in cervical cancer women with a high prevalence of HIV infection. The detection rate is generally lower, but in select subgroups of women, it was comparable to that reported elsewhere. This is the first report of the use of SLN biopsy in a substantial group of HIV-infected women.

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35. Accuracy of anal cytology in predicting histological HSIL: baseline results from the Australian Study of the Prevention of Anal Cancer (SPANC)

Sexual Health ◽

10.1071/shv10n6ab35 ◽

2013 ◽

Vol 10 (6) ◽

pp. 587

Author(s):

Jennifer Roberts ◽

Clare Biro ◽

Annabelle Farnsworth ◽

Debbie Ekman ◽

Marjorie Adams ◽

...

Keyword(s):

Predictive Value ◽

Screening Program ◽

Anal Carcinoma ◽

Hiv Positive ◽

Homosexual Men ◽

Significant Difference ◽

Anal Cytology ◽

Cytological Abnormality ◽

Sensitivity Specificity ◽

The Bethesda System

Background Anal cytology may form the basis of a future screening program to prevent anal carcinoma. Therefore, the accuracy of anal Papanicolaou tests in detecting histological HSIL needs to be evaluated. Methods: SPANC is a 3-year prospective study in homosexual men aged ≥35 years. At each of five visits, men undergo collection of a ThinPrep® anal cytological sample, high-resolution anoscopy (HRA) and biopsy of any abnormalities. Cytology is reported using the Bethesda system. Histology is reported using lower anogenital squamous terminology. Results: 351 men had a baseline visit by end July 2013. Median age was 49 (range: 35–79) years and 101 (28.8%) men were HIV positive. Anal cytology results were: unsatisfactory in 21 (6.0%), negative in 143 (40.7%), ASC-US in 51 (14.5%), LSIL in 22 (6.3%), ASC-H in 45 (12.8%) and HSIL in 69 (19.7%). 293 of 351 (83.5%) men had baseline histology. The most severe abnormality for each was: negative for SIL in 98 (33.4%), LSIL in 87 (29.7%) and HSIL in 108 (36.9%). Anal cytology sensitivity for histological HSIL (at ASC-US threshold) was 79.0%. Specificity was 53.8%. Positive predictive value (PPV) of any cytological abnormality for histological HSIL was 44.4% and PPV of HSIL cytoprediction was 63.8%. Negative predictive value (NPV) was 84.6%. Overall there was no significant difference between HIV positive and negative men with respect to sensitivity, specificity, PPV or NPV. Conclusions: These results indicate that histological HSIL is common in homosexual men. The finding of any cytological abnormality should prompt HRA. However, both cytology and HRA can miss or underestimate significant lesions in a single screening.

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Performance of LED Fluorescence Microscopy for the Diagnosis of Pulmonary Tuberculosis in HIV Positive Individuals in Addis Ababa, Ethiopia

Tuberculosis Research and Treatment ◽

10.1155/2015/794064 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Konjit Getachew ◽

Tamrat Abebe ◽

Abebaw Kebede ◽

Adane Mihret ◽

Getachew Melkamu

Keyword(s):

Pulmonary Tuberculosis ◽

Predictive Value ◽

Addis Ababa ◽

Sputum Sample ◽

Cross Sectional Study ◽

Hiv Positive ◽

Smear Microscopy ◽

Lower Sensitivity ◽

Cross Sectional ◽

Sensitivity Specificity

Background. Despite its lower sensitivity, smear microscopy remains the main diagnostic method for pulmonary tuberculosis (PTB) in resource-limited countries as TB culturing methods like LJ (Lowenstein-Jensen) are expensive to use as a routine base. This study aimed to evaluate the performance of LED-FM for the diagnosis of PTB in HIV positive individuals.Methods. Cross-sectional study was conducted in Zewditu Memorial Hospital and Teklehaimanot Health Center HIV/ART clinics in Addis Ababa, Ethiopia. Each sample was stained with ZN and Auramine O staining and examined with bright-field microscope and LED-FM microscope, respectively. LJ culture was used as a reference.Results. Out of 178 study participants, twenty-four (13.5%) patients were confirmed as positive for MTB with LJ culture. The yield of ZN microscopy and LED-FM in direct and concentrated sample was 3.9%, 8.4%, 6.2%, and 8.4%, respectively. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of direct ZN microscopy were 29.2%, 100%, 100%, and 90.1%, respectively, and of LED-FM microscopy in direct sputum sample were 62.5%, 100%, 100%, and 94.5%, respectively.Conclusion. LED-FM has better sensitivity for the diagnosis of PTB in HIV positive individuals as compared to conventional ZN microscopy. LED-FM can be used as an alternative to conventional ZN microscopy.

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Isothermal Amplification of Nucleic Acids Coupled with Nanotechnology and Microfluidic Platforms for Detecting Antimicrobial Drug Resistance and Beyond

Advanced Pharmaceutical Bulletin ◽

10.34172/apb.2022.004 ◽

2021 ◽

Author(s):

Seyedeh Zahra Alamolhoda ◽

Nosratollah Zarghami ◽

Houman Kahroba ◽

Ahmad Mehdipour ◽

Mohammad Pourhassan-Moghaddam ◽

...

Keyword(s):

Nucleic Acids ◽

Point Of Care ◽

High Sensitivity ◽

Molecular Techniques ◽

Isothermal Amplification ◽

High Tech ◽

Antimicrobial Drug Resistance ◽

Resource Limited ◽

Accessible Point ◽

Sensitivity Specificity

Antibiotic resistance is one of the serious health-threatening issues globally, the control of which is indispensable for rapid diagnosis and treatment because of the high prevalence and risks of pathogenicity. Traditional and molecular techniques are relatively expensive, complex, and non-portable, requiring facilities, trained personnel, and high-tech laboratories. Widespread and timely-detection is vital to the better crisis management of rapidly spreading infective diseases, especially in low-tech regions and resource-limited settings. Hence, the need for inexpensive, fast, simple, mobile, and accessible point-of-care (POC) diagnostics is highly demanding. Among different biosensing methods, the isothermal amplification of nucleic acids is favorite due to their simplicity, high sensitivity/specificity, rapidity, and portability, all because they require a constant temperature to work. Isothermal amplification methods are utilized for detecting various targets, including DNA, RNA, cells, proteins, small molecules, ions, and viruses. In this paper, we discuss various platforms, applications, and potentials of isothermal amplification techniques for biosensing of antimicrobial resistance. We also evaluate the potential of these methods, coupled with the novel and rapidly-evolving platforms offered by nanotechnology and microfluidic devices.

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