A novel vertical flow assay for point of care measurement of iron from whole blood

Remote areas of many low and middle income (LMI) countries have poor access to HIV viral load (HIV VL) testing. The SAMBA-II (Simple Amplification-based Assay) Semi-Q Whole Blood Test (Diagnostics for the Real World (DRW), Cambridge, UK) is a point of care assay which uses leucodepletion technology to allow whole blood testing in remote settings. 1540 consecutive HIV-positive clinic patients in Cameroon (250), UK (633), Ukraine (412) and Zimbabwe (245) donated venous blood (all countries) and finger-prick blood (all except UK) for testing on SAMBA-II. SAMBA II results were compared with simultaneous plasma results on the Abbott RealTime HIV-1 (Abbott Molecular, Des Plaines, IL) viral load assay and interpreted as either <1000 RNA copies/ml or ≥1000 RNA copies/ml. For 1528 venous whole-blood samples tested on SAMBA II, overall percent agreement with the reference test at a cut-off of HIV VL ≥1000 cps/ml was 96.9% (1480/1528 95% CI 95.9-97.7), negative percent agreement 97.7% (1259/1289 95% CI 96.7-98.4), positive percent agreement 92.5% (221/239 95% CI 88.4-95.5). For 854 finger-prick samples there was 95.0% (811/854 95% CI 93.3-96.3) overall percent agreement; negative percent agreement 98.0% (625/638, 95% CI 96.5-98.9); positive percent agreement 86.1% (186/216 95% CI 80.8-90.4). These rose to 93.5% (82.1, 98.6), 97.6% (95.6, 98.8) and 95.6% (93.3, 97.3) after exclusion of aberrant results from the Ukraine centre. These results show a high level of agreement between SAMBA-II and a laboratory-based assay. SAMBA-II has a performance that is suitable to use as a VL point of care assay in remote settings

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P384 Therapeutic drug monitoring: performance of the first lateral flow-based Point of Care test for the quantification of infliximab in a finger prick

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjab076.508 ◽

2021 ◽

Vol 15 (Supplement_1) ◽

pp. S396-S397

Author(s):

A Ametzazurra ◽

J Pascual ◽

L Del Rio ◽

A Maguregui ◽

D Nagore ◽

...

Keyword(s):

Therapeutic Drug Monitoring ◽

Drug Monitoring ◽

Whole Blood ◽

Limit Of Detection ◽

Point Of Care ◽

Package Insert ◽

Lateral Flow ◽

Therapeutic Drug ◽

Limit Of Quantification ◽

Finger Prick

Abstract Background Promonitor Quick IFX is a lateral flow test (LFT) for the quantification of infliximab (IFX) in human whole blood (finger prick or venous) or serum in 20 minutes. This LFT is based on a sandwich immunoassay to quantify either the reference IFX or biosimilars. This abstract describes the studies performed to establish the analytical specifications of the product. Methods Clinical and Laboratory Standards Institute (CLSI) guidelines were followed for the evaluation of the analytical specifications of the LFT in whole blood and serum matrices: Linearity (EP-06-A), Detection capability (EP17-A2), Interfering substances (EP07, 3rd Edition), Intermediate precision (EP05-A3) and Bias evaluation study for Biosimilars (EP10-A3). Results were obtained in combination with the automated portable reader PQreader. A Datamatrix provided with each Promonitor Quick IFX kit contains the calibration information required for the PQreader to measure the Control and Test lines and report the IFX concentration. Results The linear assay range was determined to be 1-58 µg/mL in whole-blood and 0.6-67 µg/mL in serum according to the processes indicated in the Package Insert. The Limit of Blank is 0.8 μg/mL, the Limit of Detection and Lower Limit of Quantification (LLoQ) are 1.1 μg/mL, and the Upper Limit of Quantification (ULoQ) is 15.4 μg/mL. There was no effect on assay performance when each of the following substances were added to samples with 0, 3, and 7 μg/mL of IFX: Haemoglobin (>1000 mg/dL), Bilirubin (>40 mg/dL), Triglycerides (>1500 mg/dL), HAMA (160 AU/mL), Rheumatoid factor (200 IU/mL), EDTA (5.4 mg/mL), Heparin (51 U/mL), Citrate (11.4%), Vedolizumab (60 μg/mL) and Adalimumab (20.25 μg/mL). Repeatability and within-device precision results obtained for the positive samples are shown in the table below. The negative samples showed a negative result in all the measurements. A bias study showed that Promonitor Quick IFX can quantify CT-P13, SB2 and GP1111 biosimilars throughout the measurement range with a maximum bias of 14%. Conclusion Promonitor Quick IFX is the first LFT available for true Point of Care testing of patients treated with IFX with just a finger prick sample. It provides quick turnaround time to facilitate therapeutic drug monitoring and aid immediate decision making in the doctor office or hospitals with an excellent analytical performance.

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Analytical Performance of a FRET-Based Point-of-Care Immunoassay for the Quantitation of C-Reactive Protein in Serum and Finger Prick Capillary Whole Blood

10.26434/chemrxiv.14368487.v1 ◽

2021 ◽

Author(s):

Rukmini Reddy ◽

Raj Srikrishnan ◽

Bayda Bahur ◽

Kevin Chon ◽

Stefan Westin ◽

...

Keyword(s):

Whole Blood ◽

Care Setting ◽

Point Of Care ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Blood Collection ◽

C Reactive Protein ◽

Reactive Protein ◽

Inflammatory Status ◽

Finger Prick

<div><p>Time-resolved fluorescence resonance energy transfer (FRET) provides a useful technology for immunoassay measurement of proteins, This has been used to develop an immunoassay for C-reactive protein (Procise CRP<a>™</a>) that provides point-of-care measurement of CRP in less than 4 minutes using 20 µL of either whole blood or serum. Analytical studies of the assay on the ProciseDx™ analyzer were performed to characterize its measurement capabilities.</p><p><br></p><p>Sensitivity, specificity, linearity, and precision - including reproducibility of finger prick blood collection and testing, suitable for routine clinical use in a point-of-care setting were demonstrated for the CRP assay. It also showed excellent analytical agreement with a current commercial CRP test.</p><p> </p><p><br></p><p>These results indicate the Procise CRP assay is useful for obtaining fast and accurate CRP quantitation in a point of care setting that can aid in the immediate assessment of patients’ inflammatory status. </p></div><div><br></div>

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Quantum Dots-Based Point-of-Care Measurement of Procalcitonin in Finger-Prick Blood and Venous Whole Blood Specimens

Laboratory Medicine ◽

10.1093/labmed/lmz025 ◽

2019 ◽

Vol 51 (1) ◽

pp. 34-40

Author(s):

Junming Tang ◽

Yan Jiang ◽

Zhijun Ge ◽

Haifeng Wu ◽

Huajun Chen ◽

...

Keyword(s):

Quantum Dots ◽

Whole Blood ◽

Point Of Care ◽

Venous Blood ◽

Reference Method ◽

High Sensitivity ◽

Detection Range ◽

Cutoff Value ◽

Finger Prick ◽

Blood Specimens

Abstract Objective To determine whether the performance of a new quantum dots–based point-of-care test (POCT) devices is qualified for procalcitonin testing. Methods Finger-prick and venous blood specimens from 153 patients were measured with a quantum dots–based POCT device; the results were compared with those from the reference method. Results The quantum dots–based POCT device correlated well with the reference method in measuring plasma, venous whole blood, and finger-prick blood. No significant bias was observed (−0.08 ng/mL). At 0.5 ng per mL cutoff value, the concordances were 96.6%, 94.6%, and 90.5% for plasma, venous whole blood, and finger-prick blood, respectively. And at 2 ng per mL cutoff value, the concordances were 98.0%, 96.6%, and 95.3%, respectively. Conclusions The quantum dots–based POCT device measured procalcitonin with multiple specimen types, high sensitivity, wide detection range, and short turnaround time. It would allow a more widespread use of procalcitonin and help lessen the burden of overcrowding in healthcare facilities in China.

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Analytical Performance of a FRET-Based Point-of-Care Immunoassay for the Quantitation of C-Reactive Protein in Serum and Finger Prick Capillary Whole Blood

10.26434/chemrxiv.14368487 ◽

2021 ◽

Author(s):

Rukmini Reddy ◽

Raj Srikrishnan ◽

Bayda Bahur ◽

Kevin Chon ◽

Stefan Westin ◽

...

Keyword(s):

Whole Blood ◽

Care Setting ◽

Point Of Care ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Blood Collection ◽

C Reactive Protein ◽

Reactive Protein ◽

Inflammatory Status ◽

Finger Prick

<div><p>Time-resolved fluorescence resonance energy transfer (FRET) provides a useful technology for immunoassay measurement of proteins, This has been used to develop an immunoassay for C-reactive protein (Procise CRP<a>™</a>) that provides point-of-care measurement of CRP in less than 4 minutes using 20 µL of either whole blood or serum. Analytical studies of the assay on the ProciseDx™ analyzer were performed to characterize its measurement capabilities.</p><p><br></p><p>Sensitivity, specificity, linearity, and precision - including reproducibility of finger prick blood collection and testing, suitable for routine clinical use in a point-of-care setting were demonstrated for the CRP assay. It also showed excellent analytical agreement with a current commercial CRP test.</p><p> </p><p><br></p><p>These results indicate the Procise CRP assay is useful for obtaining fast and accurate CRP quantitation in a point of care setting that can aid in the immediate assessment of patients’ inflammatory status. </p></div><div><br></div>

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Standardised protocol for a prospective cross-sectional multicentre clinic-based evaluation of two dual point-of-care tests for the screening of HIV and syphilis in men who have sex with men, sex workers and pregnant women

BMJ Open ◽

10.1136/bmjopen-2020-044479 ◽

2020 ◽

Vol 10 (11) ◽

pp. e044479

Author(s):

Keyword(s):

Pregnant Women ◽

Sex Workers ◽

Whole Blood ◽

Point Of Care ◽

Research Approach ◽

Cross Sectional ◽

Predictive Values ◽

Finger Prick ◽

Sex With Men ◽

Point Of Care Tests

IntroductionDual point-of-care tests (POCTs) for detecting antibodies to HIV and syphilis have been developed for use with venous whole blood, serum/plasma or finger-prick capillary whole blood. Several tests are commercially available showing encouraging performance compared with ‘gold-standard’ reference tests in laboratory-based studies. However, data on their performance in the field are limited. This prospective cross-sectional study will conduct a clinic-based evaluation to assess the performance characteristics and acceptability to end-users of two dual HIV/syphilis POCTs for the screening of HIV and syphilis among men who have sex with men (MSM), sex workers (SWs) and pregnant women (PW). This master protocol outlines the overall research approach that will be used in seven countries.Method and analysisMSM, SWs and PW presenting at clinic evaluation sites in high, low and middle-income countries will be enrolled. The (WHO preapproved) POCTs to be evaluated are SD Bioline HIV/Syphilis Duo (Abbott) and Dual Path Platform HIV-Syphilis Assay (Chembio). Finger-prick blood will be collected to perform POCTs and compared with laboratory results (venepuncture blood). Procedures will be carried out by trained healthcare staff and tests performed according to the manufacturers’ directions. Sample size was calculated based on local prevalence of HIV and syphilis. The sensitivity, specificity, positive and negative predictive values for each POCT will be calculated. The study is ongoing with recruitment expected to be completed in all countries by mid to late 2021.Ethics and disseminationThis core protocol was independently peer reviewed and approved by the Research Project Review Panel (RP2) of the WHO Department of Sexual and Reproductive Health and Research and by the WHO Ethics Review Committee (ERC). The protocol has been adapted to individual countries and approved by RP2, ERC and institutional review boards at each site. Results will be disseminated through peer-reviewed journals and relevant conferences.

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Comparison of 2 glucose analytical methodologies in immature Kemp’s ridley sea turtles: dry chemistry of plasma versus point-of-care glucometer analysis of whole blood

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211001830 ◽

2021 ◽

pp. 104063872110018

Author(s):

Justin R. Perrault ◽

Michael D. Arendt ◽

Jeffrey A. Schwenter ◽

Julia L. Byrd ◽

Kathryn A. Tuxbury ◽

...

Keyword(s):

Whole Blood ◽

Point Of Care ◽

Sea Turtles ◽

Sample Volume ◽

Specific Reference ◽

Volume Data ◽

Analytical Methodology ◽

Glucose Determination ◽

Kemp's Ridley Sea Turtles ◽

Kemp's Ridley

Blood glucose measurements provide important diagnostic information regarding stress, disease, and nutritional status. Glucose analytical methodologies include dry chemistry analysis (DCA) of plasma and point-of-care (POC) glucometer analysis of whole blood; however, these 2 methods differ in cost, required sample volume, and processing time. Because POC glucometers use built-in equations based on features of mammalian blood to convert whole blood measurements to plasma equivalent units, obtained glucose data must be compared and validated using gold-standard chemistry analytical methodology in reptiles. For in-water, trawl-captured, immature Kemp’s ridley sea turtles ( Lepidochelys kempii) from Georgia, USA, we observed significant, positive agreement between the 2 glucose determination methods; however, the glucometer overestimated glucose concentrations by 1.4 mmol/L on average in comparison to DCA and produced a wider range of results. The discordance of these results suggests that POC glucometer glucose data should be interpreted in the context of methodology- and brand-specific reference intervals along with concurrent packed cell volume data.

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PERFORMANCE CHARACTERISTICS OF A FRET-BASED IMMUNOASSAY FOR QUANTITATION OF INFLIXIMAB ON A POINT-OF-CARE INSTRUMENT SYSTEM

Inflammatory Bowel Diseases ◽

10.1093/ibd/izaa347.135 ◽

2021 ◽

Vol 27 (Supplement_1) ◽

pp. S57-S57

Author(s):

Edgar Ong ◽

Ruo Huang ◽

Richard Kirkland ◽

Michael Hale ◽

Larry Mimms

Keyword(s):

Whole Blood ◽

Limit Of Detection ◽

Point Of Care ◽

Quantitative Detection ◽

Therapeutic Drug ◽

Analytical Sensitivity ◽

Sample Type ◽

Hook Effect ◽

Limit Of Quantitation ◽

Assay Precision

Abstract Introduction A fast (<5 min), time-resolved fluorescence resonance energy transfer (FRET)-based immunoassay was developed for the quantitative detection of infliximab (IFX) and biosimilars for use in therapeutic drug monitoring using only 20 µL of fingerstick whole blood or serum at the point-of-care. The Procise IFX assay and ProciseDx analyzer are CE-marked. Studies were performed to characterize analytical performance of the Procise IFX assay on the ProciseDx analyzer. Methods Analytical testing was performed by spiking known amounts of IFX into negative serum and whole blood specimens. Analytical sensitivity was determined using limiting concentrations of IFX. Linearity was determined by testing IFX across the assay range. Hook effect was assessed at IFX concentrations beyond levels expected to be found within a patient. Testing of assay precision, cross-reactivity and potential interfering substances, and biosimilars was performed. The Procise IFX assay was also compared head-to-head with another CE-marked assay: LISA-TRACKER infliximab ELISA test (Theradiag, France). The accuracy of the Procise IFX assay is established through calibrators and controls traceable to the WHO 1st International Standard for Infliximab (NIBSC code: 16/170). Results The Procise IFX assay shows a Limit of Blank, Limit of Detection, and Lower Limit of Quantitation (LLoQ) of 0.1, 0.2, and 1.1 µg/mL in serum and 0.6, 1.1, and 1.7 µg/mL in whole blood, respectively. The linear assay range was determined to be 1.7 to 77.2 µg/mL in serum and whole blood. No hook effect was observed at an IFX concentration of 200 µg/mL as the value reported as “>ULoQ”. Assay precision testing across 20 days with multiple runs and reagent lots showed an intra-assay coefficient of variation (CV) of 2.7%, an inter-assay CV of <2%, and a total CV of 3.4%. The presence of potentially interfering/cross-reacting substances showed minimal impact on assay specificity with %bias within ±8% of control. Testing of biosimilars (infliximab-dyyb and infliximab-abda) showed good recovery. A good correlation to the Theradiag infliximab ELISA was obtained for both serum (slope=1.01; r=0.99) and whole blood (slope=1.01; r=0.98) samples (Figure 1). Conclusion Results indicate that the Procise IFX assay is sensitive, specific, and precise yielding results within 5 minutes from both whole blood and serum without the operator needing to specify sample type. Additionally, it shows very good correlation to a comparator assay that takes several hours and sample manipulation to yield results. This makes the Procise IFX assay ideal for obtaining fast and accurate IFX quantitation, thus allowing for immediate drug level dosing decisions to be made by the physician during patient treatment.

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