Fingerstick Whole Blood Research Articles

Validation of a Novel Fluorescent Lateral Flow Assay for Rapid Qualitative and Quantitative Assessment of Total Anti-SARS-CoV-2 S-RBD Binding Antibody Units (BAU) from Plasma or Fingerstick Whole-Blood of COVID-19 Vaccinees.

Background: Limited commercial LFA assays are available to provide a reliable quantitative measurement of the total binding antibody units (BAU/mL) against the receptor-binding domain of the SARS-CoV-2 spike protein (S-RBD). Aim: This study aimed to evaluate the performance of the fluorescence LFA FinecareTM 2019-nCoV S-RBD test along with its reader (Model No.: FS-113) against the following reference methods: (i) the FDA-approved GenScript surrogate virus-neutralizing assay (sVNT); and (ii) three highly performing automated immunoassays: BioMérieux VIDAS®3, Ortho VITROS®, and Mindray CL-900i®. Methods: Plasma from 488 vaccinees was tested by all aforementioned assays. Fingerstick whole-blood samples from 156 vaccinees were also tested by FinecareTM. Results and conclusions: FinecareTM showed 100% specificity, as none of the pre-pandemic samples tested positive. Equivalent FinecareTM results were observed among the samples taken from fingerstick or plasma (Pearson correlation r = 0.9, p < 0.0001), suggesting that fingerstick samples are sufficient to quantitate the S-RBD BAU/mL. A moderate correlation was observed between FinecareTM and sVNT (r = 0.5, p < 0.0001), indicating that FinecareTM can be used for rapid prediction of the neutralizing antibody (nAb) post-vaccination. FinecareTM BAU results showed strong correlation with VIDAS®3 (r = 0.6, p < 0.0001) and moderate correlation with VITROS® (r = 0.5, p < 0.0001) and CL-900i® (r = 0.4, p < 0.0001), suggesting that FinecareTM can be used as a surrogate for the advanced automated assays to measure S-RBD BAU/mL.

Evaluation of SAMBA II: A Qualitative and Semiquantitative HIV Point-of-Care Nucleic Acid Test.

Point-of-care (POC) nucleic acid tests (NATs) have potential to diagnose acute HIV infection and monitor persons taking pre-exposure prophylaxis or antiretroviral therapy (ART). POC NATs have not yet been evaluated in the US. From June 2018-March 2019, we conducted a cross-sectional evaluation of the Simple Amplification-Based Assay version II (SAMBA II) POC NAT. People with HIV (PWH) and persons testing for HIV were tested with the SAMBA II qualitative (Qual) whole blood (WB) test. From April-September 2019, the Qual test was used on persons who were ART-naive, and SAMBA II Semi-quantitative (Semi-Q) WB was used with ART-experienced PWH. Both were performed on unprocessed venipuncture (VP) and, when indicated by protocol, fingerstick (FS) WB and plasma. SAMBA results were compared with Abbott RealTime HIV-1 polymerase chain reaction results on plasma. We calculated sensitivity, specificity, and concordance between tests. SAMBA was used in 330 visits among 280 participants: 202 (61.2%) visits from PWH, and 128 (38.8%) from HIV-negative persons. Qual test sensitivity with ART-naive participants was 91.4% [32/35, 95% confidence interval (CI): 77.6% to 97.0%] using VP WB and 100% (27/27, 95% CI: 87.5% to 100%) using FS WB. Specificity was 100% using both specimen types. Concordance between the gold standard and Semi-Q at 1000 copies/mL among PWH on ART was 97.7% (86/88, 95% CI: 92.1% to 99.4%) and 100% (30/30, 95% CI: 88.7% to 100%) using VP and FS WB, respectively. The SAMBA II POC NATs showed high sensitivity, specificity, and concordance with the gold standard assay, indicating its potential use in diagnostics and monitoring. Future work will evaluate POC NAT implementation in the US.

Dual rapid lateral flow immunoassay fingerstick wholeblood testing for syphilis and HIV infections is acceptable and accurate, Port-au-Prince, Haiti.

BackgroundDual rapid tests for HIV and syphilis infections allow for detection of HIV infection and syphilis at the point-of-care. Those tests have been evaluated in laboratory settings and show excellent performance but have not been evaluated in the field. We evaluated the field performance of the SD BIOLINE HIV/Syphilis Duo test in Port-au-Prince, Haiti using whole blood fingerprick specimens.MethodsGHESKIO (Haitian Study Group for Kaposi’s Sarcoma and Opportunistic Infections) clinic attendees 18 years of age or older were invited to participate. Venipuncture blood specimens were used for reference testing with standard commercially available tests for HIV and syphilis in Haiti. The sensitivity and specificity of the Duo test compared to the reference standard were calculated. The exact binomial method was used to determine 95 % confidence intervals (CI).ResultsOf 298 study participants, 237 (79.5 %) were female, of which 49 (20.7 %) were pregnant. For the HIV test component, the sensitivity and specificity were 99.2 % (95 % CI: 95.8 %, 100 %) and 97.0 % (95 % CI: 93.2 %, 99.0 %), respectively; and for the syphilis component were 96.5 % (95 % CI: 91.2 %, 99.0 %) and 90.8 % (95 % CI: 85.7 %, 94.6 %), respectively. In pregnant women, the sensitivity and specificity of the HIV test component were 93.3 % (95 % CI: 68.0 %, 99.8 %) and 94.1 % (95 % CI: 80.3 %, 99.3 %), respectively; and for the syphilis component were 100 % (95 % CI:81.5 %, 100 %) and 96.8 % (95 % CI:83.3 %, 99.9 %), respectively.ConclusionThe Standard Diagnostics BIOLINE HIV/Syphilis Duo dual test performed well in a field setting in Haiti and should be considered for wider use.

A Finger-Stick Whole-Blood HIV Self-Test as an HIV Screening Tool Adapted to the General Public

BackgroundIn 2013, the French Health Authority approved the use of HIV self-tests in pharmacies for the general public. This screening tool will allow an increase in the number of screenings and a reduction in the delay between infection and diagnosis, thus reducing the risk of further infections. We previously compared 5 HIV-self test candidates (4 oral fluid and one whole blood) and demonstrated that the whole blood HIV test exhibited the optimal level of performance (sensitivity/specificity). We studied the practicability of an easy-to-use finger-stick whole blood HIV self-test “autotest VIH®”, when used in the general public.Methods and MaterialsThis multicenter cross-sectional study involved 411 participants from the Parisian region (AIDES and HF association) between April and July 2014 and was divided into 2 separate studies: one evaluating the capability of participants to obtain an interpretable result using only the information notice, and a second evaluating the interpretation of test results, using a provided chart.ResultsA total of 411 consenting participants, 264 in the first study and 147 in the second, were included. All participants were over 18 years of age. In the first study, 99.2% of the 264 participants correctly administered the auto-test, and 21.2% needed, upon their request, telephone assistance. Ninety-two percent of participants responded that the test was easy/very easy to perform, and 93.5% did not find any difficulty obtaining a sufficient good quantity of blood. In the second study, 98.1% of the 147 participants correctly interpreted the results. The reading/interpretation errors concerned the negative (2.1%) or the indeterminate (3.3%) auto-tests.ConclusionsThe success rate of handling and interpretation of this self-test is very satisfactory, demonstrating its potential for use by the general public and its utility to increase the number of opportunities to detect HIV patients.

Sensitivity of Five Rapid HIV Tests on Oral Fluid or Finger-Stick Whole Blood: A Real-Time Comparison in a Healthcare Setting

BackgroundHealth authorities in several countries recently recommended the expansion of human immunodeficiency virus (HIV) antibody testing, including the use of rapid tests. Several HIV rapid tests are now licensed in Europe but their sensitivity on total blood and/or oral fluid in routine healthcare settings is not known.Methods and Findings200 adults with documented HIV-1 (n = 194) or HIV-2 infection (n = 6) were prospectively screened with five HIV rapid tests using either oral fluid (OF) or finger-stick whole blood (FSB). The OraQuick Advance rapid HIV1/2® was first applied to OF and then to FSB, while the other tests were applied to FSB, in the following order: Vikia HIV 1/2®, Determine HIV 1–2®, Determine® HIV-1/2 Ag/Ab Combo® and INSTI HIV-1/HIV-2®. Tests negative on FSB were repeated on paired serum samples. Twenty randomly selected HIV-seronegative subjects served as controls, and the results were read blindly. Most patients had HIV-1 subtype B infection (63.3%) and most were on antiretroviral therapy (68.5%). Sensitivity was 86.5%, 94.5%, 98.5%, 94.9%, 95.8% and 99% respectively, with OraQuick OF, OraQuick FSB, Vikia, Determine, Determine Ag/Ab Combo and INSTI (p<0.0001). OraQuick was less sensitive on OF than on FSB (p = 0.008). Among the six patients with three or more negative tests, two had recent HIV infection and four patients on antiretroviral therapy had undetectable plasma viral load. When patients positive in all the tests were compared with patients who had at least one negative test, only a plasma HIV RNA level <200 cp/ml was significantly associated with a false-negative result (p = 0.009). When the 33 rapid tests negative on FSB were repeated on serum, all but six (5 negative with OraQuick, 1 with INSTI) were positive. The sensitivity of OraQuick, Determine and Determine Ag/Ab Combo was significantly better on serum than on FSB (97.5%, p = 0.04; 100%, p = 0.004; and 100%, p = 0.02, respectively).ConclusionWhen evaluated in a healthcare setting, rapid HIV tests were less sensitive on oral fluid than on finger-stick whole blood and less sensitive on finger-stick whole blood than on serum.

HIV Load Testing with Small Samples of Whole Blood

Access to human immunodeficiency virus (HIV) viral load (VL) testing is of paramount importance for the success of antiretroviral therapy treatment campaigns throughout the world. In many countries, limited laboratory infrastructure and transport capacities preclude a substantial number of people infected with HIV from accessing the necessary testing. Point-of-care diagnostic testing methods for those with HIV infection provide a compelling solution to addressing this challenge. To facilitate ease of use in such tests, finger-stick whole blood (WB) would constitute an ideal sample type if test performance equivalent to laboratory testing could be ensured. To determine the diagnostic sensitivity of a VL assay based on small volumes of WB, we analyzed 1,094 sample pairs of 1 ml of plasma and 10 microl of WB from donors confirmed to be HIV positive. The probability of detecting HIV nucleic acids in 10 microl of blood was 59.3% (95% confidence interval, 54.9 to 63.6%), 85.1% (80.0 to 90.2%), 91.5% (88.1 to 95%), and 100% when the corresponding plasma samples had an undetectable VL, a detectable VL less than 40 viral copies/ml (cp/ml), a VL between 40 and 4,000 cp/ml, and a VL greater than 4,000 cp/ml, respectively. Capillary blood and venous blood yielded comparable diagnostic sensitivities. Furthermore, our data indicate that WB could be used to monitor VL changes after highly active antiretroviral therapy (HAART) started. Thus, we have demonstrated the feasibility of small volumes of venous and finger-stick WB as valid samples for VL testing. This approach should facilitate the development of robust point-of-care HIV VL tests.

A Comparison of Patient Acceptance of Fingerstick Whole Blood and Oral Fluid Rapid HIV Screening in an Emergency Department

Although whole blood rapid HIV testing has a greater sensitivity and specificity compared with oral fluid (OF) testing, patients prefer HIV testing using OF specimen collection. Whether patient preference for noninvasive collection methods affects acceptance of HIV screening in clinical practice, however, is unknown. To determine whether patient acceptance of fingerstick whole blood (FWB) and OF rapid HIV screening differs in an emergency department setting. From May 1 to June 30, 2007, triage-based testers offered rapid HIV screening to patients. OF and FWB tests were available on alternate days. Eligible patients were medically stable, > or =15 years of age, and not known to be HIV infected. : Two thousand two hundred one patients were referred for HIV screening: 1089 on OF days and 1112 on FWB screening days. Screening rates with OF and FWB were similar (61.9% vs. 59.1%, P = 0.18). Although most reasons why patients declined screening were similar for the groups, the specimen collection method was the primary reason for refusal by 25 patients who declined FWB screening compared with none of the patients who declined OF screening. Among emergency department patients, the preference for 1 rapid test collection modality over another has a minimal effect on actual screening rates.

Evaluation of seven Cholestech L.D.X analyzers for total cholesterol determinations

We assessed the performance of seven Cholestech L.D.X lipid analyzers under tightly controlled laboratory conditions for accuracy and precision in accordance with analytical guidelines of the National Cholesterol Education Program (NCEP). Venous heparinized whole blood (VB) and plasma (VP), venous serum (VS), and capillary fingerstick whole blood (FB) were collected from 18 individuals. Total cholesterol (TC) concentration was measured in VB, VP, and VS on all seven instruments. Three instruments were used for TC measurements of FB. Reference cholesterol values for each individual were generated in the same laboratory with a standardized method. The within-run coefficients of variation (CVs) for all instruments with a Level I pool (1560 mg/L, n = 10) ranged from 1.3% to 1.8% (mean = 1.59%). The between-run CVs with the same pool ranged from 2.2% to 3.4% (mean = 2.84%, n = 10). Correlation coefficients derived from comparison of total cholesterol values generated by the instruments for each specimen type vs the reference cholesterol values were all > 0.97. The average bias for all instruments for each sample type was 1.9% (FB), 4.3% (VB), 6.6% (VP), and 7.0% (VS). Predicted cholesterol concentration for each sample type from regression curves for total cholesterol at the suggested NCEP clinical decision cutoff values of 2000 and 2400 mg/L, respectively, were 2049 and 2431 mg/L for FB, 2081 and 2469 mg/L for VB, 2122 and 2522 mg/L for VP, and 2121 and 2521 mg/L for VS.