Semiquantitative Test Research Articles

Advanced imidazole-functionalized metal-organic framework-based dual-mode sensor for rapid detection of FLU pesticide residues in food

In this study, an advanced imidazole-functionalized 2D metal-organic framework (HBU-169), {[Cd2(L)2H2O]2(H2O)}·(4H2O)·(DMF) was presented, which possesses both fluorescent properties and peroxidase activity. HBU-169 demonstrates the ability to detect fluazinam (FLU) via fluorescent and colorimetric modes. In the fluorescent mode, a pronounced fluorescence quenching is observed, with the limit of detection (LOD) of 1.68 μM. The mechanism may involve dynamic quenching process and competitive absorption of excitation energy. The method could be utilized for rapid in-situ imaging detection of pesticide residues on cabbage surface. In the colorimetric mode, a semi-quantitative test paper was developed, featuring visible color changes and smartphone-assisted detection. The mechanism was attributed to the catalytic effect of HBU-169. A high-throughput method combining fluorescent and colorimetric modes were established for FLU detection. This study provides a promising avenue for assessing the safety of FLU-contaminated food and holds potential for application in ensuring the safety of other agricultural products.

Prevalence of Torque Teno Virus, Hepatitis and Cytomegalovirus Infection in Iranian Patients With Different Types of leukemia

Background and Objectives: Torque teno virus (TTV) infection can be seen in different types of leukemia and may affect clinical outcomes. This study aims to investigate the prevalence of TTV, hepatitis B and C virus, and cytomegalovirus (CMV) in Iranian patients with different types of leukemia. Methods: In this descriptive cross-sectional study, 95 patients with different types of leukemia participated. The molecular prevalence of TTV infection was evaluated using the semi-nested PCR method. The prevalence of HBs-Ag and HCV-Ab viruses was measured by the ELISA method. Also, the prevalence of active CMV infection was investigated by the semi-quantitative antigenemia test. The data analysis was done in SPSS software version 12 using logistic regression analysis, chi-square test, and Fisher’s exact test. Results: The TTV infection was found in 40 out of 95 patients (42.1%). The presence of HBs-Ag was reported in 27 out of 95 patients (28.4%). HCV-Ab was found in 18 out of 69 patients (26.1%), and active CMV infection was found in 11 out of 69 (15.9%). Among 40 leukemia patients with TTV infection, 15 (37.5%) had hepatitis B, 14 (35%) had hepatitis C, and 7 (17.5%) had CMV infection. Conclusion: The high prevalence of single or comorbid TTV infection among Iranian patients with leukemia emphasizes the importance of this virus in causing or aggravating the clinical complications observed in these patients.

B-050 A comparison of two semi-quantitative tests, Abbott’s Advise DX SARS-CoV-2 IgG II and Beckman Coulter’s Access SARS-COV-2 IgG II, for measuring IgG antibody levels after Sars-CoV-2 Pfizer-BioNTech vaccination

Abstract Background Using 219 samples collected from volunteer employees of our lab, obtained in different times after Sars-CoV-2 Pfizer-BioNTech vaccination, we compared two semi-quantitative tests: Methods Abbott's AdviseDx SARS-CoV-2 IgG II and Beckman Coulter’s Access SARS-CoV-2 IgG II assay. Both assays detect IgG antibodies to the receptor binding domain of the S1 subunit of the spike protein of SARS-CoV-2 in serum and plasma of tested individuals. For the Beckman test, AMR is from 0 to 450 AU/ml with cut off for positive test 10 AU/ml; for the Abbott test, AMR is from 0 to 25000 AU/ml with cut off for positive test 100 AU/ml. Results Using a fitted regression line, it appears that the best correlation between these two tests was found in the lower value range, below 25AU/ml for Beckman test and 4000 AU/ml for Abbott test (R-squared value of 0.842 and y=87.165x). For higher antibody levels, the result distribution resembles a binary pattern, which we find very interesting. We will discuss possible explanations of this finding. Conclusions

B-275 Trends of urine drug testing findings in a pediatric hospital from 2019 to 2023

Abstract Background Semi-quantitative immunoassays (IA) are commonly used as the initial urine drug screen (UDS), with positive results confirmed by additional testing. However, substantial false negative (FN) rates have been reported in the classes of opioids and amphetamines. In our pediatric hospital, a semi-quantitative comprehensive urine drug testing by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF) MS (referred as QTOF) is offered as either a direct order or a reflexive order following positive IA UDS. The lab also reflexes to run an IA UDS with every direct QTOF order. This study presents paired urine drug IA and QTOF results in the classes of opiate, synthetic opioid, and amphetamine/methamphetamine between 2019 and 2023 to understand trends and to evaluate assay accuracy. Methods Paired results from IA (Siemens Atellica) and QTOF (Sciex 4600) were analyzed with reporting cutoff concentrations from representative drugs in each class listed in Figure 1. The opiate class reported on QTOF includes 6-monoacetylmorphine, morphine, hydrocodone, codeine and metabolites. The synthetic opioid class includes buprenorphine, fentanyl, levorphanol, methadone, naloxone, oxycodone, tramadol and metabolites. Simultaneous findings of opiate and synthetic opioid were counted as the opiate class. FN rate of IA was calculated using QTOF as the reference. Results As shown in Figure 1, QTOF testing nearly doubled from 2019 to 2023, with an expected high FN rate in the synthetic opioid class and alarmingly rising FN rates in opiate and amphetamine classes. Within the synthetic opioid class, percentage of positive fentanyl results increased from 37.6% to 59.0% in 5 years, and ∼10% are only positive for norfentanyl, which is detected in very few commercial fentanyl IAs. Conclusions Our study clearly demonstrates the gap in pediatric toxicology investigation, reporting high FN rates in common drug classes by urine IA, calling for more comprehensive and sensitive UDS to be broadly adopted.

Personal characteristics and transmission dynamics associated with SARS-CoV-2 semi-quantitative PCR test results: an observational study from Belgium, 2021-2022.

Following harmonization efforts by the Belgian National Reference Center for SARS-CoV-2, semi-quantitative PCR test (SQ-PCR) results, used as a proxy for viral load, were routinely collected after performing RT-qPCR tests. We investigated both the personal characteristics associated with SQ-PCR results and the transmission dynamics involving these results. We used person-level laboratory test data and contact tracing data collected in Belgium from March 2021 to February 2022. Personal characteristics (age, sex, vaccination, and laboratory-confirmed prior infection) and disease stage by date of symptom onset were analyzed in relation to SQ-PCR results using logistic regression. Vaccine effectiveness (VE) against a high viral load (≥107 copies/mL) was estimated from the adjusted probabilities. Contact tracing involves the mandatory testing of high-risk exposure contacts (HREC) after contact with an index case. Odds ratios for test positivity and high viral load in HREC were calculated based on the SQ-PCR result of the index case using logistic regression models adjusted for age, sex, immunity status (vaccination, laboratory-confirmed prior infection), variant (Alpha, Delta, Omicron), calendar time, and contact tracing covariates. We included 909,157 SQ-PCR results of COVID-19 cases, 379,640 PCR results from index cases, and 72,052 SQ-PCR results of HREC. High viral load was observed more frequently among recent cases, symptomatic cases, cases over 25 years of age, and those not recently vaccinated (>90 days). The vaccine effectiveness (VE) of the primary schedule in the first 30 days after vaccination was estimated at 47.3% (95%CI 40.8-53.2) during the Delta variant period. A high viral load in index cases was associated with an increased test positivity in HREC (OR 2.7, 95%CI 2.62-2.79) and, among those testing positive, an increased likelihood of a high viral load (OR 2.84, 95%CI 2.53-3.19).

Effect of transcutaneous electrical nerve stimulation on neuro-sensory disturbance after orthognathic surgery: a randomized clinical trial.

The present study aims to determine the effect of Transcutaneous Electrical Nerve Stimulation (TENS) on neuro-sensory disturbance after orthognathic surgery. In a randomized clinical trial, the participants via split-mouth sampling were randomly divided into two intervention (n=27) and control (n=27) groups. In the intervention group, participants received TENS physiotherapy. TENS physiotherapy was performed on the day after surgery, 1, 2, 3, and 4 weeks after surgery, along with prescriptions for the use of painkillers. On the control group, no physical therapy was performed and the patients only used painkillers (immediately after the operation). Paresthesia was evaluated using the 2-point discrimination (TPD) test and the semi-quantitative sensory-neural disorders test called brush stroke 6 months after the surgical procedures. Self-reported sensory-neural disorders were measured and reported for each patient before and 6 months after surgery using the visual analog scale (VAS). A total of 54 patients participated in this study. The mean TPD score in the TENS group and the control group 6 months after the operation were 5.76 (SD=0.73) and 6.14 (SD=0.54), respectively (P=0.003). The mean VAS score in the TENS group and the control group 6 months after the operation was 6.48 (SD=0.50) and 5.80 (SD=0.63), respectively (P=0.005). Also, 66.7 and 38.9% in the TENS and control groups, respectively, performed the brush stroke test correctly (P=0.007). In sum, the benefits of TENS physiotherapy can be effective in reducing complications such as pain in dental surgery treatments or orthognathic surgeries.

Utility of Point-of-Care Diagnosis of Chronic Heart Failure Using an Express Test for Semi-Quantitative Determination of NT-proBNP Levels.

To evaluate the accuracy of a rapid test for semi-quantitative determination of NT-proBNP levels in the diagnosis of CHF in comparison with quantitative assessment; to study the strength of the association of the results of this NT-proBNP test with indicators of the CHF severity. The concentration of NT-proBNP was determined in 44 patients at bedside both semi-quantitatively using an express test (BioTest, Novosibirsk) and quantitatively in a laboratory. In 11 patients, the severity of CHF was assessed with the CHF Clinical Status Scale (CSS). Echocardiography was performed in all patients. The sensitivity of the quantitative and semi-quantitative tests coincided and was 95%. The specificity of the quantitative test was 100% in our study, whereas the semi-quantitative test showed a specificity of 92%. The negative predictive value of either test was 96%. The diagnostic accuracy was 98% and 93%, respectively. In patients with significantly high NT-proBNP concentrations, the semi-quantitative test demonstrated a reduced ability to verify values above 1800 pg/ml; in patients with threshold concentrations, the semi-quantitative test showed an increased subthreshold sensitivity. Increases in the NT-proBNP concentration correlated with the severity of CHF according to the stage of the disease. Due to the sufficiently high sensitivity, specificity, ease of use, and speed of obtaining results, the rapid test for semi-quantitative measuring NT-proBNP is promising for outpatient screening bedside diagnosis of CHF and in the emergency room to confirm or exclude CHF. When determining the dynamics of NT-proBNP during the treatment of CHF, the use of the semi-quantitative rapid test with visual assessment of the results may produce an error compared to the quantitative assessment, which will probably not allow tracking the effect of therapy or predicting exacerbation of the disease.

A prospective evaluation of the diagnostic accuracy of the point-of-care VISITECT CD4 Advanced Disease test in seven countries.

CD4 measurement is pivotal in the management of advanced HIV disease. VISITECT® CD4 Advanced Disease (AccuBio Limited, Alva, UK; VISITECT) is an instrument-free, point-of-care, semi-quantitative test allowing visual identification of a CD4 ≤200 cells/µl, or >200 cells/µl from finger-prick or venous blood. As part of a diagnostic accuracy study of FUJIFILM SILVAMP TB LAM (clinicaltrials.gov: NCT04089423), people living with HIV of ≥18 years old were prospectively recruited in seven countries from outpatient departments if a tuberculosis symptom was present, and from inpatient departments. Participants provided venous blood for CD4 measurement using flow cytometry (reference standard) and finger-prick blood for VISITECT (index text), performed at point-of-care. Sensitivity, specificity, and positive and negative predictive values of VISITECT to determine a CD4 ≤200 cells/µl were evaluated. Among 1604 participants, the median flow cytometry CD4 was 367 (IQR 128-626) cells/µl and 521 (32.5%) had a CD4 ≤200 cells/µl. VISITECT sensitivity was 92.7% (483/521, 95% CI 90.1-94.7%) and specificity was 61.4% (665/1083, 95% CI 58.4-64.3%). For participants with a CD4 between 0-100, 101-200, 201-300, 301-500, and >500 cells/µl, VISITECT misclassified 4.5% (95% CI 2.5-7.2%), 12.5 (95% CI 8.0-18.2%), 74.1% (95% CI 67.0-80.5%), 48.0% (95% CI 42.5-53.6%), and 22.6% (95% CI 19.3-26.3%), respectively. VISITECT's sensitivity, but not specificity, met the World Health Organization's minimal sensitivity and specificity threshold of 80% for point-of-care CD4 tests. VISITECT's quality needs to be assessed and its accuracy optimized. VISITECT´s utility as CD4 triage test should be investigated.

Semiquantitative Paper-Based Microfluidic Surrogate Virus Neutralization Test for SARS-CoV-2 Neutralizing Antibodies.

Neutralizing antibodies (nAbs) produced from infection or vaccination play an important role in acquired immunity. Determining virus-specific nAb titers is a useful tool for measuring aquired immunity in an individual. The standard methods to do so rely on titrating serum samples against live virus and monitoring viral infection in cultured cells which requires high biosafety level containment. The surrogate virus neutralization test (sVNT) reduces the biohazards and it is suitable for designing rapid test device in a lateral flow assay (LFA) format. Here, we introduce the fabrication and development of a unique paper-based LFA device for determining the level of SARS-CoV-2 nAb in a sample with a semiquantitative direct colorimetric readout. A LFA-based gradient assay design was used to facilitate the sVNT, where the spike glycoprotein receptor binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2) stand in as proxies for viruses and cells, respectively. The gradient assay employed multiple test dots of ACE2 spotted in increasing concentration along the sample flow path and gold nanoparticle-conjugated RBD for readout. In this way, the number of developed spots is inversely proportional to the concentration of nAbs present in the sample. The assay was tested with both standard solutions of nAb as well as human serum samples. We have demonstrated that the device can effectively provide semiquantitative test results of nAbs by direct instrument-free colorimetric detection.

Performance Evaluation of Semi-quantitative Urine Albumin Creatinine Ratio Using Meditape UC-11A Strip Test

The Urine Albumin/Creatinine Ratio (uACR) is one of the earliest markers of glomerular disorders. A comparative study of semi-quantitative urine uACR and quantitative uACR tests was carried out using Meditape UC-11A test strips on the Sysmex UC-3500 (automated urinalysis instrument) and Roche Cobas 501, respectively. A total of 213 retrospective data of urine chemistry tests were collected. Semi-quantitative urine albumin, creatinine, and uACR data were obtained using Meditape UC-11A strips on Sysmex UC-3500, whereas quantitative data were obtained using Roche Cobas c501. A weighted Cohen's Kappa agreement, sensitivity, specificity, PPV, NPV, and accuracy were analyzed using data from both instruments. The Kappa values for urine albumin, creatinine, and uACR between the semi-quantitative and quantitative methods were 0.83 (CI 0.771– 0.880), 0.535 (CI 0.417–0.652), and 0.691 (CI 0.606–0.775), respectively. The sensitivity, specificity, PPV, NPV, and accuracy of semi-quantitative methods were 90%, 73.3%, 75%, 89.2%, and 81.2%, respectively. The semi-quantitative uACR test on the UC-3500 showed excellent performance and could be used as a screening test for early detection of impaired kidney function.

A novel, green and affordable semi-quantitative limit test for 2-aminobutanol impurity in ethambutol hydrochloride bulk and tablets

The pharmacopoeial limit test for the impurity 2-aminobutanol (AB) in ethambutol hydrochloride (ETB) relies on florescence measurement using a fluorometer. However, this instrument is often unavailable in many laboratories due to its cost. A novel colorimetric method was therefore developed using genipin, an amine-reactive reagent, to react with AB, producing a blue color. The color intensity was subsequently measured using a more affordable UV-vis spectrophotometer. To overcome matrix effects, the standard addition technique was incorporated. The test effectively detected AB at concentrations as low as 0.125% in ETB, below the compendial limit of 1.0%. The analysis of ETB bulk and tablets showed consistent semi-quantitative results with the USP method. Furthermore, it aligned with green chemistry by eliminating the use of organic solvents and employing safe, naturally derived reagent. In summary, the proposed method provides a reliable, green, and cost-effective alternative for analyzing AB in ETB, ensuring compliance with pharmacopeial standards.

Monitoring changes in hydric properties of treated stone material with conservation products by time-sequential IR thermography

A methodological approach for a semi-quantitative non-destructive testing (NDT) of the effects on hydric properties after the application of different conservation treatments (commercial ethylsilicate and siloxane compounds with consolidant, water repellent or consolidant + water repellent properties) is presented in this study. The NDT used for this purpose is a simplified method of time-sequential infrared thermography (IRT) on stone (granite and marble, treated and untreated) from the Roman theatre of Merida (Spain), which was listed by UNESCO as World Heritage Site in 1993.As water evaporation modifies temperature intensely, IRT enables monitoring the response of the stone samples during water absorption-evaporation processes. The comparative analysis between treated and non-treated specimens was performed by calculating the rate of surface apparent temperature change (ΔoC/h) value. The capillary rising test, monitored by IRT, clearly showed a different response of the samples treated with water-repellent treatments, proving their efficiency. Samples treated with organosilicic compounds showed a large and rapid drop in apparent surface temperature, indicating that water accesses rapidly.Results from the evaporation test also show this difference. The surface apparent temperature increased immediately in samples with water-repellent treatments, in which water does not enter inside stone, but remains on the surface. Samples with ethyl silicate, again, show a greater difference with respect to untreated samples, taking longer to recover surface apparent temperature, because the water is retained inside the stone for longer.This study proved simplified time-sequential IRT as a reliable technique for assessing the efficacy of conservation treatments applied to stone materials in laboratory.

Accuracy of screening for hemolysis in plasma samples using a commercial urine dipstick

Objectives: Identification and quantification of hemolysis in serum or plasma samples is an important requirement in laboratory diagnostics; however, this is not always possible automatically, and visual sample inspection is not sufficiently accurate. We have planned this study to determine whether a commercially available urine dipstick with a hemoglobin-reactive pad could be used for this purpose. Materials and Methods: Sixty-five routine plasma samples, whose hemolysis index (HI) was previously determined on Roche Cobas 8000, were assayed with a commercial urine dipstick to obtain semi-quantitative data on plasma hemoglobin. Plasma was diluted 1:1000 in water to enter the dipstick’s range of hemoglobin measurement, and 10 µL of this dilution was applied to the hemoglobin pad. Results were visually interpreted within 60 s by comparing the pad color with that on the dipstick box label. Statistical Analysis: Semi-quantitative test results obtained with the urine dipstick were directly correlated with those of the same samples assayed on Roche Cobas 8000 using non-parametric Spearman’s correlation and agreement. Results: The sample size consisted of 40 non-hemolyzed (HI ≤0.3 g/L) and 25 hemolyzed (HI >0.3 g/L) plasma samples. Spearman’s correlation between Cobas HI and dipstick hemoglobin concentration was r = 0.96 (95% confidence interval, 0.93–0.97; P < 0.001). The concordance of hemolysis detection was 95.4%, with 1.00 sensitivity, 0.93 specificity, 1.00 negative predictive value, and 0.89 positive predictive value compared to the reference HI measurement on Cobas. The cumulative agreement between Cobas HI and the various plasma hemoglobin thresholds obtained with the dipstick was 75.4%. Conclusions: We have demonstrated here that plasma hemoglobin assessment with commercially available urine dipsticks may generate semi-quantitative test results accurate enough to influence decision-making regarding sample quality and its suitability for testing.

Semi-quantitative group testing for efficient and accurate qPCR screening of pathogens with a wide range of loads

BackgroundPathogenic infections pose a significant threat to global health, affecting millions of people every year and presenting substantial challenges to healthcare systems worldwide. Efficient and timely testing plays a critical role in disease control and transmission prevention. Group testing is a well-established method for reducing the number of tests needed to screen large populations when the disease prevalence is low. However, it does not fully utilize the quantitative information provided by qPCR methods, nor is it able to accommodate a wide range of pathogen loads.ResultsTo address these issues, we introduce a novel adaptive semi-quantitative group testing (SQGT) scheme to efficiently screen populations via two-stage qPCR testing. The SQGT method quantizes cycle threshold (Ct) values into multiple bins, leveraging the information from the first stage of screening to improve the detection sensitivity. Dynamic Ct threshold adjustments mitigate dilution effects and enhance test accuracy. Comparisons with traditional binary outcome GT methods show that SQGT reduces the number of tests by 24% on the only complete real-world qPCR group testing dataset from Israel, while maintaining a negligible false negative rate.ConclusionIn conclusion, our adaptive SQGT approach, utilizing qPCR data and dynamic threshold adjustments, offers a promising solution for efficient population screening. With a reduction in the number of tests and minimal false negatives, SQGT holds potential to enhance disease control and testing strategies on a global scale.

Rational design of peptide-based fluorescent probe for sequential recognitions of Cu(II) ions and glyphosate: Smartphone, test strip, real sample and living cells applications

A new peptide-based fluorescent probe named DMDH with easy-to-synthesize, excellent stability, good water solubility and large Stokes shift (225 nm) was synthesized for highly selective sequential detections of copper ions (Cu2+) and glyphosate (Glyp). DMDH demonstrated great detection performance towards Cu2+via strong fluorescence quenching, and forming non-fluorescence DMDH-Cu2+ ensemble. As a new promising cascade probe, the fluorescence of DMDH-Cu2+ ensemble was significantly recovered based on displacement approach after glyphosate was added. Interestingly, the limit of detections (LODs) for Cu2+ and glyphosate were 40.6 nM and 10.6 nM, respectively, which were far lower than those recommended by the WHO guidelines for drinking water. More importantly, DMDH was utilized to evaluate Cu2+ and glyphosate content in three real water samples, demonstrating that its effectiveness in water quality monitoring. Additionally, it is worth noting that DMDH was also applied to analyze Cu2+ and glyphosate in living cells in view of significant cells permeability and low cytotoxicity. Moreover, DMDH soaked in filter paper was used to create qualitative test strips and visually identify Cu2+ and glyphosate through significant color changes. Furthermore, smartphone RGB color recognition provided a new method for semi-quantitative testing of Cu2+ and glyphosate in the absence of expensive instruments.

Point-of-care N-terminal pro-brain natriuretic peptide testing in patients with heart failure: data from the DREAM study

Aim. To compare the blood levels of N-terminal pro-brain natriuretic peptide (NTproBNP), determined using a Russian semi-quantitative point-of-care test and quantitative laboratory tests, depending on the presence and severity of heart failure (HF) and left ventricular (LV) function.Material and methods. This Diagnosis of chRonic hEart fAilure using a NTproBNP test Multicenter study (DREAM) was conducted in 79 patients with HF and 24 healthy individuals. Blood NT-proBNP concentrations assessed using an immunochromatographic semiquantitative rapid test were compared with quantitative laboratory test results, severity of heart failure, and LV function.Results. The study showed that the NT-proBNP rapid test results were highly correlated (correlation coefficient 0,74) with the quantitative test. The NT-proBNP level assessed by the rapid test increases in patients with higher NYHA HF class and does not differ significantly from the quantitative test grades. The sensitivity, specificity, positive predictive value, and negative predictive value of the test result relative to natriuretic peptide quantification were 0,97, 0,78, 0,91, and 0,93, respectively. Sensitivity, specificity, positive and negative predictive value of the test result regarding NYHA classes II-IV were 0,95, 0,85, 0,95 and 0,85, and regarding LV ejection fraction <50% — 1,0, 0,24, 0,24, and 1,0, respectively. False-positive rate in the healthy individuals' group were low (4%).Conclusion. The results of the NT-proBNP rapid test demonstrated acceptable diagnostic accuracy compared to quantitative assessment in patients with HF of varying severity and LV ejection fraction.

Accuracy, use and acceptability of the VISITECT CD4 semi-quantitative test to advance HIV disease screening in routine programmatic settings in Tanzania

BackgroundThe available few laboratory-based CD4 assay for People Living with HIV (PLHIV) experience supply stock-outs and instrument breakdowns in developing countries, affecting the ability to diagnose Advance HIV disease (AHD). We evaluated the performance of the VISITECT CD4 point of care test among healthcare workers in HIV program in Tanzania. MethodsA retrospective diagnostic accuracy study was conducted among PLHIV who received both the VISITECT CD4 and a standard-of-care. Acceptability of the VISITECT CD4 by healthcare workers was assessed using a structured questionnaire. Both FACS Count and Pima CD4 assay were considered as reference standards. Findings were summarized as proportions with 95 % confidence intervals (CI). Data were analyzed using STATA 17 (StataCorp, College Station, TX). ResultsA total of 1370 PLHIV were tested using VISITECT CD4 across 20 facilities between 3 April and 14 September 2022. The median age was 37 (Interquartile range (IQR):29–46). Overall, 897 (65.5 %) were females and 449 had both VISITECT CD4 test and standard of care. The sensitivity and specificity were; 95.9 % (95 % CI: 91.8 %–98.3 %) and 78.3 % (95 % CI: 73.0 %–83.0 %) respectively. 47 healthcare workers used the VISITECT CD4, of whom 57.5 % were non-laboratory healthcare workers. Majority of the healthcare workers were of the opinion that the training was adequate and VISITECT CD4 was easy and useful in clinical decisions. ConclusionThe VISITECT CD4 test was accurate, useable and acceptable among healthcare workers in Tanzania. The scale up of VISITECT CD4 should consider development of training curriculum and the use of job aids particularly for non-laboratory healthcare workers.

An up-conversion fluorescence lateral-flow immunoassay for rapid detection of Daratumumab in serum protein electrophoresis clinical samples

BackgroundDaratumumab (DARA) is a commonly used monoclonal antibody (mAb) drug for the treatment of multiple myeloma (MM). Its appearance as a visible abnormal band in the γ-region of a serum protein electrophoresis (SPEP) gel may interfere with the SPEP result interpretation. With the advantages of portability and rapid testing capabilities, up-conversion fluorescence lateral-flow immunoassay (LFA) can be an ideal solution to detect DARA interference. MethodsAn up-conversion fluorescence LFA strip was designed and constructed to perform semi-quantitative DARA testing in clinical samples. The LFA strip test was evaluated for limit of detection (LOD), dynamic range, and analytical interference. ResultsTo demonstrate the clinical utility of the LFA strip, 43 SPEP-positive patient serum samples were tested for the presence of DARA, and the results exactly matched the DARA usage history in patient medical records. ConclusionsThe performance of the up-conversion fluorescence LFA strip meets the purpose of clarifying DARA interference in SPEP results. It may be used as an independent and objective confirmation of the presence of DARA in clinical samples. The LFA strip offers a cost-effective rapid on-site test to check for DARA interference alongside standard SPEP equipment, which significantly improves the interpretation of ambiguous SPEP results involving DARA, and does not intervene the current SPEP workflow in clinical laboratory practice.

Semi-quantitative metalloproteinase-8 rapid test for the prediction of adverse pregnancy outcomes in patients with preterm premature rupture of membranes

ObjectiveWe aimed to determine whether the semi-quantitative metalloproteinase-8 (MMP-8) bedside test is a worthwhile indicator in reflecting the severity of of intra-amniotic inflammation (IAI) and in predicting adverse pregnancy outcomes. Study DesignThis retrospective cohort study comprised 76 singleton-pregnant women admitted to the Seoul National University Bundang Hospital with a diagnosis of preterm premature rupture of membranes (preterm PROM) between 20 weeks 0 days and 33 weeks 6 days of gestation who underwent trans-abdominal amniocentesis to confirm intra-amniotic infection by positive results for aerobic/anaerobic bacteria, fungi, and genital mycoplasma and evaluate lung maturity. The semi-quantitative MMP-8 rapid test kit employs a colourimetric assay to quantify MMP-8 levels in amniotic fluid (AF), expressing results from 0 to 100 percent. Participants were divided into three groups: group 1, including negative MMP-8 test with colour scale of 0 % (negative, n = 17); group 2, including positive MMP-8 test with colour scale < 51 % (weak positive, n = 21); and group 3, including positive MMP-8 test with colour scale of 51 %–100 % (strong positive, n = 38). ResultsApproximately 78 % (59/76) of the participants showed a positive MMP-8 test result; all culture-proven AF samples (33.3 % [25/75]) yielded positive MMP-8 test, categorizing these patients into either group 2 or group 3. A significant trend was observed where the rate of positive culture-proven samples increased with the progression from group 1 (negative) to group 3 (strong positive). Both white blood cell counts in AF and maternal serum C-reactive protein levels were found to escalate with the progression of test results from negative to strong positive. This progression was associated with an increased risk of spontaneous preterm birth within 48 h, 7 days, and 14 days from amniocentesis and within 34 weeks of gestation. ConclusionThe more the test results progress from negative to strong positive, the shorter the interval from amniocentesis to delivery becomes, and the higher the risk of intra-amniotic infection, spontaneous preterm delivery, and other perinatal complications. This relationship highlights the critical value of the semi-quantitative MMP-8 rapid test in predicting adverse pregnancy outcomes in patients with preterm PROM.

Tafenoquine following G6PD screening versus primaquine for the treatment of vivax malaria in Brazil: A cost-effectiveness analysis using a transmission model.

Malaria transmission modelling has demonstrated the potential impact of semiquantitative glucose-6-phosphate dehydrogenase (G6PD) testing and treatment with single-dose tafenoquine for Plasmodium vivax radical cure but has not investigated the associated costs. This study evaluated the cost-effectiveness of P. vivax treatment with tafenoquine after G6PD testing using a transmission model. We explored the cost-effectiveness of using tafenoquine after G6PD screening as compared to usual practice (7-day low-dose primaquine (0.5 mg/kg/day) without G6PD screening) in Brazil using a 10-year time horizon with 5% discounting considering 4 scenarios: (1) tafenoquine for adults only assuming 66.7% primaquine treatment adherence; (2) tafenoquine for adults and children aged >2 years assuming 66.7% primaquine adherence; (3) tafenoquine for adults only assuming 90% primaquine adherence; and (4) tafenoquine for adults only assuming 30% primaquine adherence. The incremental cost-effectiveness ratios (ICERs) were estimated by dividing the incremental costs by the disability-adjusted life years (DALYs) averted. These were compared to a willingness to pay (WTP) threshold of US$7,800 for Brazil, and one-way and probabilistic sensitivity analyses were performed. All 4 scenarios were cost-effective in the base case analysis using this WTP threshold with ICERs ranging from US$154 to US$1,836. One-way sensitivity analyses showed that the results were most sensitive to severity and mortality due to vivax malaria, the lifetime and number of semiquantitative G6PD analysers needed, cost per malaria episode and per G6PD test strips, and life expectancy. All scenarios had a 100% likelihood of being cost-effective at the WTP threshold. The main limitations of this study are due to parameter uncertainty around our cost estimates for low transmission settings, the costs of G6PD screening, and the severity of vivax malaria. In our modelling study that incorporated impact on transmission, tafenoquine prescribed after a semiquantitative G6PD testing was highly likely to be cost-effective in Brazil. These results demonstrate the potential health and economic importance of ensuring safe and effective radical cure.