Development of a Fit-For-Purpose Multi-Marker Panel for Early Diagnosis of Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) suffers from a lack of an effective diagnostic method, which hampers improvement in patient survival. Carbohydrate antigen 19-9 (CA19-9) is the only FDA-approved blood biomarker for PDAC, yet its clinical utility is limited due to suboptimal performance. Liquid chromatography-mass spectrometry (LC-MS) has emerged as a burgeoning technology in clinical proteomics for the discovery, verification, and validation of novel biomarkers. A plethora of protein biomarker candidates for PDAC have been identified using LC-MS, yet few has successfully transitioned into clinical practice. This translational standstill is owed partly to insufficient considerations of practical needs and perspectives of clinical implementation during biomarker development pipelines, such as demonstrating the analytical robustness of proposed biomarkers which is critical for transitioning from research-grade to clinical-grade assays. Moreover, the throughput and cost-effectiveness of proposed assays ought to be considered concomitantly from the early phases of the biomarker pipelines for enhancing widespread adoption in clinical settings. Here, we developed a fit-for-purpose multi-marker panel for PDAC diagnosis by consolidating analytically robust biomarkers as well as employing a relatively simple LC-MS protocol. In the discovery phase, we comprehensively surveyed putative PDAC biomarkers from both in-house data and prior studies. In the verification phase, we developed a multiple-reaction monitoring (MRM)-MS-based proteomic assay using surrogate peptides that passed stringent analytical validation tests. We adopted a high-throughput protocol including a short gradient (<10 min) and simple sample preparation (no depletion or enrichment steps). Additionally, we developed our assay using serum samples, which are usually the preferred biospecimen in clinical settings. We developed predictive models based on our final panel of 12 protein biomarkers combined with CA19-9, which showed improved diagnostic performance compared to using CA19-9 alone in discriminating PDAC from non-PDAC controls including healthy individuals and patients with benign pancreatic diseases. A large-scale clinical validation is underway to demonstrate the clinical validity of our novel panel.

Validation of the VirCapSeq-VERT system for differential diagnosis, detection, and surveillance of viral infections.

IMPORTANCE: Broad range assay for accurate and sensitive diagnostics.

A Hydrogen Bonded Non-Porous Organic-Inorganic Framework for Measuring Cysteine in Blood Plasma and Endogenous Cancer Cell.

An imbalance in cysteine (Cys) levels in the cells and plasma has been identified as the risk indicator for various human diseases. The structural similarity of cysteine with its congener homocysteine and glutathione offers challenges in its measurement. Herein, we report a hydrogen-bonded organic-inorganic framework of Cu(II) (HOIF) for the selective detection of cysteine over other biothiols. The non-fluorescent HOIF showed 12-fold green emission in the presence of cysteine. The monomeric unit of HOIF is stabilized via intermolecular hydrogen bonds, resulting in a non-porous network structure. Non-interference from homocysteine, glutathione, and other competitive bio-analytes revealed explicit affinity of HOIF for cysteine. Fluorimetric titration showed a wide working concentration window (650 nM-800 µM) for measuring cysteine in an aqueous medium. The mechanistic investigation involving HRMS, EPR, and UV-vis spectroscopic studies revealed the decomplexation of HOIF with Cys, resulting in a fluorescence turn-on response from the luminescent ligand. Validation using a commercial dye, "Cysteine Green", confirmed the prospect of HOIF for early diagnostic purposes. Utilizing the fluorescence turn-on property of HOIF in the presence of cysteine, we measured cysteine quantitatively in the blood plasma samples. Bio-imaging of endogenous cysteine in cancer cells indicated the ability of HOIF to monitor the intracellular cysteine.

Analytical validation of the LungLB test: a 4-color fluorescence in-situ hybridization assay for the evaluation of indeterminate pulmonary nodules.

BACKGROUND: Evaluation of indeterminate pulmonary nodules (IPNs) often creates a diagnostic conundrum which may delay the early detection of lung cancer. Rare circulating genetically abnormal cells (CGAC) have previously demonstrated utility as a biomarker for discriminating benign from malignant small IPNs in the LungLB assay. CGAC are identified using a unique 4-color fluorescence in-situ hybridization (FISH) assay and are thought to reflect early cell-based events in lung cancer pathogenesis and the anti-tumor immune response. LungLB is a prognostic tool that combines the CGAC biomarker and clinical features to aid in IPN evaluation by improving the stratification of patient risk of malignancy. METHODS: Herein we describe the analytical performance of the LungLB blood test. Analytical validation was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines with adaptations for rare cell-based assays. Multiple operators, reagent lots, and assay runs were tested to examine accuracy, precision, reproducibility, and interfering factors. RESULTS: The FISH probes used in the LungLB assay demonstrate 100% sensitivity and specificity for their intended chromosomal loci (3q29, 3p22.1, 10q22.3 and 10cen). LungLB demonstrates analytical sensitivity of 10 CGAC per 10,000 lymphocytes analyzed, 100% analytical specificity, and high linearity (R2 = 0.9971). Within run measurements across 100 samples demonstrated 96% reproducibility. Interfering factors normally found in blood (lipemia, biotin) and exposure to adverse temperatures (-20ºC or 37ºC) did not interfere with results. Sample stability was validated to 96 hours. CONCLUSION: The analytical performance of LungLB in this validation study successfully demonstrates it is robust and suitable for everyday clinical use.

Development and validation of method for the simultaneous determination of sulfamethazine, trimethoprim and doxycycline in veterinary formulation using high performance liquid chromatography.

Sulfamethazine (SMZ), trimethoprim (TMP) and doxycycline (DOXY) are drugs of choice used in the treatment of intestinal and respiratory infections that affect poultry and swine. The aim of this study was develop and validate a simple, sensitive and fast method for the simultaneous determination of SMZ, TMP and DOXY in veterinary formulations by high-performance liquid chromatography. The separation was performed on a Macherey-Nagel C8 analytical column (4 × 125 mm, 5 µm), with a flow rate of 0.5 ml min-1 and detection at 268, 270 and 350 nm, for SMZ, TMP and DOXY, respectively. All measurements were performed in acetonitrile-water (45:55 v/v; pH 3.0). The analytical curves were linear (r > 0.9997) in the concentration range of 5.0-35.0 µg ml-1 for SMZ, 1.0-7.0 µg ml-1 for TMP and 7.0-13.0 µg ml-1 for DOXY. The method proved to be precise, robust, accurate and selective. In accelerated stability, the sample was analyzed for 6 months, with no major variations observed in organoleptic analysis and pH. Therefore, the developed method was proved to be suitable for routine quality control analyses for the simultaneous determination of SMZ, TMP and DOXY in pharmaceutical formulations.

The Analytical Validity of Stride Detection and Gait Parameters Reconstruction Using the Ankle-Mounted Inertial Measurement Unit Syde®.

The increasing use of inertial measurement units (IMU) in biomedical sciences brings new possibilities for clinical research. The aim of this paper is to demonstrate the accuracy of the IMU-based wearable Syde® device, which allows day-long and remote continuous gait recording in comparison to a reference motion capture system. Twelve healthy subjects (age: 23.17 ± 2.04, height: 174.17 ± 6.46 cm) participated in a controlled environment data collection and performed a series of gait tasks with both systems attached to each ankle. A total of 2820 strides were analyzed. The results show a median absolute stride length error of 1.86 cm between the IMU-based wearable device reconstruction and the motion capture ground truth, with the 75th percentile at 3.24 cm. The median absolute stride horizontal velocity error was 1.56 cm/s, with the 75th percentile at 2.63 cm/s. With a measurement error to the reference system of less than 3 cm, we conclude that there is a valid physical recovery of stride length and horizontal velocity from data collected with the IMU-based wearable Syde® device.

Analytical demands to use whole-genome sequencing in precision oncology.

Interrogating the tumor genome in its entirety by whole-genome sequencing (WGS) offers an unprecedented insight into the biology and pathogenesis of cancer, with potential impact on diagnostics, prognostication and therapy selection. WGS is able to detect sequence as well as structural variants and thereby combines central domains of cytogenetics and molecular genetics. Given the potential of WGS in directing targeted therapeutics and clinical decision-making, we envision a gradual transition of the method from research to clinical routine. This review is one out of three within this issue aimed at facilitating this effort, by discussing in-depth analytical validation, clinical interpretation and clinical utility of WGS. The review highlights the requirements for implementing, validating and maintaining a clinical WGS pipeline to obtain high-quality patient-specific data in accordance with the local regulatory landscape. Every step of the WGS pipeline, which includes DNA extraction, library preparation, sequencing, bioinformatics analysis, and data storage, is considered with respect to its logistics, necessities, potential pitfalls, and the required quality management. WGS is likely to drive clinical diagnostics and patient care forward, if requirements and challenges of the technique are recognized and met.

Analytical evaluation of a GAD65 antibodies chemiluminescence immunoassay for CSF in neurological syndromes.

OBJECTIVES: Antibodies against glutamic acid decarboxylase isoform 65 (GAD-Ab) have been found in different severe neurological conditions associated with altered synthesis of γ-aminobutyric acid (GABA). Serum GAD-Ab can be found in up to 90 % of patients with type 1 diabetes mellitus (T1DM), mostly at relatively low concentrations, while high concentrations of GAD-ab are thought to be more frequently associate to a neurological condition, with levels 100-folds higher than those found in T1DM. Although CSF testing is recommended when suspecting a GAD-associated neurological syndrome, no commercial immunoassay is validated for this use and no cut-off is internationally recognized to support the diagnosis. METHODS: In this study we validated CSF testing of GAD-Ab on an automated chemiluminescence (CLIA) immunoassay that had previously shown good agreement with ELISA on serum. RESULTS: We tested 43 CSF from patients with typical GAD-associated neurological disorders and patients with other neurological conditions, identifying a clinical cut-off of 18 kIU/L that discriminated GAD-disease with an area under the curve (AUC) of 0.921. CLIA showed good analytical performances on repeatability and recovery tests in CSF and confirmed an excellent agreement with ELISA. CONCLUSIONS: GAD-Ab associated neurological disorders are rare but CSF testing for GAD-Ab is a common request for neurologists when suspecting an insidious autoimmune central nervous system disease. CLIA platforms are expected to be increasingly adopted in clinical laboratories due to their flexibility and reliability, therefore studies on decisional levels should be implemented for improving the interpretation and utilization of laboratory data.

Current status of the analytical validation of next generation sequencing applications for pharmacogenetic profiling.

BACKGROUND: Analytical validity is a prerequisite to use a next generation sequencing (NGS)-based application as an in vitro diagnostic test or a companion diagnostic in clinical practice. Currently, in the United States and the European Union, the intended use of such NGS-based tests does not refer to guided drug therapy on the basis of pharmacogenetic profiling of drug metabolizing enzymes, although the value of pharmacogenetic testing has been reported. However, in research, a large variety of NGS-based tests are used and have been confirmed to be at least comparable to array-based testing. METHODS AND RESULTS: A systematic evaluation was performed screening and assessing published literature on analytical validation of NGS applications for pharmacogenetic profiling of CYP2C9, CYP2C19, CYP2D6, VKORC1 and/or UGT1A1. Although NGS applications are also increasingly used for implementation assessments in clinical practice, we show in the present systematic literature evaluation that published information on the current status of analytical validation of NGS applications targeting drug metabolizing enzymes is scarce. Furthermore, a comprehensive performance evaluation of whole exome and whole genome sequencing with the intended use for pharmacogenetic profiling has not been published so far. CONCLUSIONS: A standard in reporting on analytical validation of NGS-based tests is not in place yet. Therefore, many relevant performance criteria are not addressed in published literature. For an appropriate analytical validation of an NGS-based qualitative test for pharmacogenetic profiling at least accuracy, precision, limit of detection and specificity should be addressed to facilitate the implementation of such tests in clinical use.

How and when to measure pH in IVF culture media: validation of a portable blood gas analyzer in two IVF culture dishes for time lapse and conventional incubators.

PURPOSE: Maintaining a stable pH at optimal level in human embryo culture media is crucial for embryo development but poses a challenge for all IVF laboratories. We validate analytically reliable conditions for pH measurement that are as close as possible to the embryo microenvironment during IVF. METHODS: This was a multicentric study. A Siemens EPOC portable blood gas analyzer was used. The analytical validation was carried out under the culture medium (Global Total HSA®) conditions of use (microdroplets, under oil overlay, in a IVF incubator with (EmbryoScope®) or without a time lapse system (K system G210+®) and using IVF dishes. The validation included repeatability ("within-run" precision), total precision (between-day precision), trueness based on inter-laboratory comparison, inaccuracy based on external quality assessment and comparison to the reference technique. We also assessed the pre-analytical medium incubation time required to obtain a target value. RESULTS: A measurement after an incubation period of 24 to 48 h is more representative of the pH to which the embryo will be exposed throughout the culture. The "within-run" and "between-day" precision show very low coefficients of variation (CV%): 0.17 to 0.22% and 0.13 to 0.34%, respectively, with IVF culture media. Trueness (% bias) range from - 0.07 to - 0.03%. We demonstrate good correlation between EPOC and reference pH electrode with an overestimation of 0.03 pH units of EPOC. CONCLUSION: Our method demonstrates good analytical performance for IVF laboratories wishing to implement a robust quality assurance system to monitor pH in embryo culture media. Compliance with stringent pre-analytical and analytical conditions is essential.

Analytical and Clinical Validation of Assays for Volumetric Absorptive Microsampling (VAMS) of Drugs in Different Blood Matrices: A Literature Review.

Volumetric absorptive microsampling (VAMS) is the newest and most promising sample-collection technique for quantitatively analyzing drugs, especially for routine therapeutic drug monitoring (TDM) and pharmacokinetic studies. This technique uses an absorbent white tip to absorb a fixed volume of a sample (10-50 µL) within a few seconds (2-4 s), is more flexible, practical, and more straightforward to be applied in the field, and is probably more cost-effective than conventional venous sampling (CVS). After optimization and validation of an analytical method of a drug taken by VAMS, a clinical validation study is needed to show that the results by VAMS can substitute what is gained from CVS and to justify implementation in routine practice. This narrative review aimed to assess and present studies about optimization and analytical validation of assays for drugs taken by VAMS, considering their physicochemical drug properties, extraction conditions, validation results, and studies on clinical validation of VAMS compared to CVS. The review revealed that the bio-analysis of many drugs taken with the VAMS technique was optimized and validated. However, only a few clinical validation studies have been performed so far. All drugs that underwent a clinical validation study demonstrated good agreement between the two techniques (VAMS and CVS), but only by Bland-Altman analysis. Only for tacrolimus and mycophenolic acid were three measurements of agreement evaluated. Therefore, VAMS can be considered an alternative to CVS in routine practice, especially for tacrolimus and mycophenolic acid. Still, more extensive clinical validation studies need to be performed for other drugs.

Analytical evaluation of the Nittobo Medical tartrate resistant acid phosphatase isoform 5b (TRACP-5b) EIA and comparison with IDS iSYS in different clinically defined populations.

OBJECTIVES: Tartrate-resistant acid phosphatase, isoform 5b (TRACP-5b) is a bone resorption marker not influenced by renal function or food intake. TRACP-5b can be measured with Nittobo Medical enzymatic-immunoassay and IDS-iSYS automated immunoassay. We evaluated the Nittobo assay and established reference ranges for a Western-European population. We compared Nittobo and IDS results in different well-defined clinical populations. METHODS: We established the limits of detection and quantification (LOD-LOQ), linearity, imprecision and the reference ranges in 119 males, 50 women (<45 years) and 120 women (>60 years) for TRACP-5b with the Nittobo assay. We compared both assays in 30 hemodialyzed (HD), and 40 stage 3-5 patients suffering from chronic kidney disease (CKD), 40 patients suffering from rheumatoid arthritis and osteoporosis and 80 post-menopausal women. We measured TRACP-5b, ß-crosslaps (ß-CTX), bone alkaline phosphatase (B-ALP) and PTH in 20 hemodialyzed (HD) and 40 CKD patients. RESULTS: LOD and LOQ were 0.02 and 0.35 U/L. CV ranged from 8.3 to 4.3% (2/5 samples presenting CV > desirable CV). Method was linear up to of 11.3 U/L. Upper and lower limits of normality were 0.8-7.6 U/L in men, 0.9-4.7 U/L in women <45 and 0.9-7.1 U/L in women >60. The regression equation between the 2 methods was Nittobo = 1.13 (95% CI: 1.09-1.16) × iSYS - 0.4 (95% CI: -0.5; -0.3). TRACP-5b and b-ALP were in their respective reference ranges for most of CKD and HD patients. That was not the case for ß-CTX, which increased with decreasing eGFR. CONCLUSIONS: Nittobo TRACP-5b presents interesting analytical features and a good concordance with IDS iSYS. These methods could thus potentially be harmonized.

Sensor Verification and Analytical Validation of Algorithms to Measure Gait and Balance and Pronation/Supination in Healthy Volunteers.

Numerous studies have sought to demonstrate the utility of digital measures of motor function in Parkinson's disease. Frameworks, such as V3, document digital measure development: technical verification, analytical and clinical validation. We present the results of a study to (1) technically verify accelerometers in an Apple iPhone 8 Plus and ActiGraph GT9X versus an oscillating table and (2) analytically validate software tasks for walking and pronation/supination on the iPhone plus passively detect walking measures with the ActiGraph in healthy volunteers versus human raters. In technical verification, 99.4% of iPhone and 91% of ActiGraph tests show good or excellent agreement versus the oscillating table as the gold standard. For the iPhone software task and algorithms, intraclass correlation coefficients (ICCs) > 0.75 are achieved versus the human raters for measures when walking distance is >10 s and pronation/supination when the arm is rotated more than two times. Passively detected walking start and end time was accurate to approx. 1 s and walking measures were accurate to one unit, e.g., one step. The results suggest that the Apple iPhone and ActiGraph GT9X accelerometers are fit for purpose and that task and passively collected measures are sufficiently analytically valid to assess usability and clinical validity in Parkinson's patients.

High-throughput fetal fraction amplification increases analytical performance of noninvasive prenatal screening.

PURPOSE: The percentage of a maternal cell-free DNA (cfDNA) sample that is fetal-derived (the fetal fraction; FF) is a key driver of the sensitivity and specificity of noninvasive prenatal screening (NIPS). On certain NIPS platforms, >20% of women with high body mass index (and >5% overall) receive a test failure due to low FF (<4%). METHODS: A scalable fetal fraction amplification (FFA) technology was analytically validated on 1264 samples undergoing whole-genome sequencing (WGS)-based NIPS. All samples were tested with and without FFA. RESULTS: Zero samples had FF < 4% when screened with FFA, whereas 1 in 25 of these same patients had FF < 4% without FFA. The average increase in FF was 3.9-fold for samples with low FF (2.3-fold overall) and 99.8% had higher FF with FFA. For all abnormalities screened on NIPS, z-scores increased 2.2-fold on average in positive samples and remained unchanged in negative samples, powering an increase in NIPS sensitivity and specificity. CONCLUSION: FFA transforms low-FF samples into high-FF samples. By combining FFA with WGS-based NIPS, a single round of NIPS can provide nearly all women with confident results about the broad range of potential fetal chromosomal abnormalities across the genome.

Liquid Biopsy Hotspot Variant Assays: Analytical Validation for Application in Residual Disease Detection and Treatment Monitoring.

BACKGROUND: Analysis of circulating tumor DNA (ctDNA) in plasma is a powerful approach to guide decisions in personalized cancer treatment. Given the low concentration of ctDNA in plasma, highly sensitive methods are required to reliably identify clinically relevant variants. METHODS: We evaluated the suitability of 5 droplet digital PCR (ddPCR) assays targeting KRAS, BRAF, and EGFR variants for ctDNA analysis in clinical use. RESULTS: We investigated assay performance characteristics for very low amounts of variants, showing that the assays had very low limits of blank (0% to 0.11% variant allele frequency, VAF) and limits of quantification (0.41% to 0.7% VAF). Nevertheless, striking differences in detection and quantification of low mutant VAFs between the 5 tested assays were observed, highlighting the need for assay-specific analytical validation. Besides in-depth evaluation, a guide for clinical interpretation of obtained VAFs in plasma was developed, depending on the limits of blank and limits of quantification values. CONCLUSION: It is possible to provide comprehensive clinical reports on actionable variants, allowing minimal residual disease detection and treatment monitoring in liquid biopsy.

Analytical validation of hepatitis B core-related antigen (HBcrAg) using dried blood spots (DBS).

Limited access to nucleic acid testing (NAT) to quantify HBV DNA levels, an essential tool to determine anti-HBV treatment eligibility, represents a significant barrier to scale up HBV diagnostic services in resource-limited countries. Hepatitis B core-related antigen (HBcrAg) has the potential to become an affordable alternative because of its low cost (US$ <15/assay) and strong correlation with HBV DNA levels in treatment-naïve patients. However, the current assay requires plasma or serum. To further facilitate its application to decentralized settings, we developed and evaluated a standardized procedure to quantify HBcrAg using dried blood spots as a tool to diagnose HBV-infected people with high viraemia. We evaluated the following elution method optimized to quantify HBcrAg: suspension of a punched blood-soaked disc (11 mm) of Whatman 903 Protein Saver Card in 450 µL of PBS 0.05% Tween 20, followed by an incubation for 4 h at room temperature and a centrifugation at 10,000 g for 10 minutes. 150 µL of DBS eluate was used to quantify HBcrAg using chemiluminescent enzyme immunoassay (LUMIPULSE® G600II, Fujirebio). The limit of detection of dried blood spot HBcrAg in relation with HBV DNA levels was 19,115 IU/mL across the five major HBV genotypes (A/B/C/D/E). A strong linear correlation was confirmed between dried blood spot HBcrAg and HBV DNA levels (r = 0.94, p < 0.0001) in samples with high viral loads (range: 3.7-7.0 log IU/mL). The coefficient of variation ranged between 4.0-11.2% for repeatability and 3.9-12.2% for reproducibility. Analytical specificity was 100% (95% CI: 83.9-100%) in HBV-negative samples. Using our elution method, it may be possible to identify HBV-infected patients with high viraemia who need antiviral therapy using dried blood spot and HBcrAg. A large-scale clinical validation is warranted in resource-limited countries.

Analytical validation of a multi-biomarker algorithmic test for prediction of progressive kidney function decline in patients with early-stage kidney disease.

BACKGROUND: The KidneyIntelX™ test applies a machine learning algorithm that incorporates plasma biomarkers and clinical variables to produce a composite risk score to predict a progressive decline in kidney function in patients with type 2 diabetes (T2D) and early-stage chronic kidney disease (CKD). The following studies describe the analytical validation of the KidneyIntelX assay including impact of observed methodologic variability on the composite risk score. METHODS: Analytical performance studies of sensitivity, precision, and linearity were performed on three biomarkers assayed in multiplexed format: kidney injury molecule-1 (KIM-1), soluble tumor necrosis factor receptor-1 (sTNFR-1) and soluble tumor necrosis factor receptor-2 (sTNFR-2) based on Clinical Laboratory Standards Institute (CLSI) guidelines. Analytical variability across twenty (20) experiments across multiple days, operators, and reagent lots was assessed to examine the impact on the reproducibility of the composite risk score. Analysis of cross-reactivity and interfering substances was also performed. RESULTS: Assays for KIM-1, sTNFR-1 and sTNFR-2 demonstrated acceptable sensitivity. Mean within-laboratory imprecision coefficient of variation (CV) was established as less than 9% across all assays in a multi-lot study. The linear range of the assays was determined as 12-5807 pg/mL, 969-23,806 pg/mL and 4256-68,087 pg/mL for KIM-1, sTNFR-1 and sTNFR-2, respectively. The average risk score CV% was less than 5%, with 98% concordance observed for assignment of risk categories. Cross-reactivity between critical assay components in a multiplexed format did not exceed 1.1%. CONCLUSIONS: The set of analytical validation studies demonstrated robust analytical performance across all three biomarkers contributing to the KidneyIntelX risk score, meeting or exceeding specifications established during characterization studies. Notably, reproducibility of the composite risk score demonstrated that expected analytical laboratory variation did not impact the assigned risk category, and therefore, the clinical validity of the reported results.

Analytical validation of the Percepta genomic sequencing classifier; an RNA next generation sequencing assay for the assessment of Lung Cancer risk of suspicious pulmonary nodules.

BACKGROUND: Bronchoscopy is a common procedure used for evaluation of suspicious lung nodules, but the low diagnostic sensitivity of bronchoscopy often results in inconclusive results and delays in treatment. Percepta Genomic Sequencing Classifier (GSC) was developed to assist with patient management in cases where bronchoscopy is inconclusive. Studies have shown that exposure to tobacco smoke alters gene expression in airway epithelial cells in a way that indicates an increased risk of developing lung cancer. Percepta GSC leverages this idea of a molecular "field of injury" from smoking and was developed using RNA sequencing data generated from lung bronchial brushings of the upper airway. A Percepta GSC score is calculated from an ensemble of machine learning algorithms utilizing clinical and genomic features and is used to refine a patient's risk stratification. METHODS: The objective of the analysis described and reported here is to validate the analytical performance of Percepta GSC. Analytical performance studies characterized the sensitivity of Percepta GSC test results to input RNA quantity, the potentially interfering agents of blood and genomic DNA, and the reproducibility of test results within and between processing runs and between laboratories. RESULTS: Varying the amount of input RNA into the assay across a nominal range had no significant impact on Percepta GSC classifier results. Bronchial brushing RNA contaminated with up to 10% genomic DNA by nucleic acid mass also showed no significant difference on classifier results. The addition of blood RNA, a potential contaminant in the bronchial brushing sample, caused no change to classifier results at up to 11% contamination by RNA proportion. Percepta GSC scores were reproducible between runs, within runs, and between laboratories, varying within less than 4% of the total score range (standard deviation of 0.169 for scores on 4.57 scale). CONCLUSIONS: The analytical sensitivity, analytical specificity, and reproducibility of Percepta GSC laboratory results were successfully demonstrated under conditions of expected day to day variation in testing. Percepta GSC test results are analytically robust and suitable for routine clinical use.

Analytical validation of an automated assay for the measurement of adenosine deaminase (ADA) and its isoenzymes in saliva and a pilot evaluation of their changes in patients with SARS-CoV-2 infection.

OBJECTIVES: The aim of the present study was to validate a commercially available automated assay for the measurement of total adenosine deaminase (tADA) and its isoenzymes (ADA1 and ADA2) in saliva in a fast and accurate way, and evaluate the possible changes of these analytes in individuals with SARS-CoV-2 infection. METHODS: The validation, in addition to the evaluation of precision and accuracy, included the analysis of the effects of the main procedures that are currently being used for SARS-CoV-2 inactivation in saliva and a pilot study to evaluate the possible changes in salivary tADA and isoenzymes in individuals infected with SARS-CoV-2. RESULTS: The automated assay proved to be accurate and precise, with intra- and inter-assay coefficients of variation below 8.2%, linearity under dilution linear regression with R2 close to 1, and recovery percentage between 80 and 120% in all cases. This assay was affected when the sample is treated with heat or SDS for virus inactivation but tolerated Triton X-100 and NP-40. Individuals with SARS-CoV-2 infection (n=71) and who recovered from infection (n=11) had higher mean values of activity of tADA and its isoenzymes than healthy individuals (n=35). CONCLUSIONS: tADA and its isoenzymes ADA1 and ADA2 can be measured accurately and precisely in saliva samples in a rapid, economical, and reproducible way and can be analyzed after chemical inactivation with Triton X-100 and NP-40. Besides, the changes observed in tADA and isoenzymes in individuals with COVID-19 open the possibility of their potential use as non-invasive biomarkers in this disease.

Development, validation, and application of an RP-HPLC method for concurrent quantification of Minoxidil and Finasteride in a topical solution for hair regrowth.

A topical solution comprising of Minoxidil (MXL) and Finasteride (FNS) for alopecia is formulated in the present work, which essentially contains a lipid-Lauroglycol FCC as a penetration enhancer. The objective of the proposed work was to develop a rapid, simple, and robust reverse phase high performance liquid chromatographic (RP-HPLC) method to determine MXL and FNS in the said formulation. Herein, the chromatographic conditions were optimized based on the theoretical principles of separation and physicochemical properties such as pKa and log P of both the Active Pharmaceutical Ingredients (APIs). The separation was accomplished on an Inertsil® ODS-3 C18 column (150mm×4.6mm; 5µm of particle size) at 25°C by using a mobile phase composed of 70:30 v/v ratio of Methanol and Milli-Q water along with 0.5% Triethylamine at pH 6.4 adjusted with Ortho Phosphoric Acid. Drug peaks showed a good resolution at 210nm. The retention times for MXL and FNS were found to be 2.40min and 6.39min, respectively. The developed method was found to be linear (R2≥0.998) in a concentration range of 5-100µg/mL for both the drugs. The method was validated according to the ICH guidelines Q2 (R1). The ability of the method to differentiate between the types formulations was demonstrated by the in vitro diffusion data performed using a highly sophisticated Strat-M® membrane. The cumulative amount of drug released (MXL and FNS) at the end of 24hours was maximum for the topical formulation containing lipids prepared using isopropyl alcohol and propylene glycol as the base.