A large staghorn stone diagnosed and managed in an asymptomatic patient using the “Kidney Injury Test (Kit)” spot urine assay: A case report
The Kidney Injury Test (KIT) Stone-Score provides an objective measure of stone burden. Unlike urinary supersaturation the KIT Stone-Scores assess underlying stone disease rather than urinary solute composition. We report a case of a 43-year-old woman with no history of nephrolithiasis who underwent an elective, voluntary KIT assay and was diagnosed with a large staghorn renal stone after an unanticipated markedly elevated score. This clinical scenario highlights the potential future use of the non-invasive urinary KIT assay as a reliable non-invasive tool to detect and monitor urinary stone disease.
Evaluation of the concordance between GluN1-GluN2 heteromer live-cell-based assay and GluN1 monomer biochip kit assay on anti-NMDAR autoantibody detection
Anti-N-methyl-d-aspartate receptor (NMDAR) antibodies are most frequently detected in autoantibody-related autoimmune encephalitis. Anti-NMDAR encephalitis mainly affects young women with ovarian teratoma, including acute to subacute onset of psychosis, seizures, consciousness disturbance, dyskinetic involuntary movements, autonomic dysfunction, and others. Diagnosis is based on the detection of anti-NMDAR autoantibodies in cerebrospinal fluid (CSF). The autoantibody recognizes the conformational epitope of the NMDA receptor. NMDA receptors contain hetero-tetramers of GluN1 (NR1) and GluN2/3 (NR2/3), in which GluN1 is essential to form functional receptors on the synaptic membrane in the brain.
Thus, the autoantibodies are detected using neurons or culture cells expressing conformational receptors on their cell membrane, the natural form in the brain. The antibodies detected using artificial GluN1 monosubunit expressing cells as the antigens have been widely used for anti-NMDAR-antibody test. In the present study two detection systems were compared, a live-cell-based assay using human embryonic kidney (HEK) 293 cells expressing both of GluN1 and GluN2B, and a commercially available GluN1-monotransfected HEK cell biochip system. As the result, both the methods were equivalent, and the clinical features of both groups were similar, suggesting both tests have equal clinical significance.
Enzymatic characterization of D-lactate dehydrogenase and application in alanine aminotransferase activity assay kit
D-lactate dehydrogenase (D-LDH) is widely used for the clinical detection of alanine aminotransferase (ALT) activity. It is a key enzyme in ALT detection kits, and its enzymatic properties directly determine sensitivity and accuracy of such kits. In this study, D-lactate dehydrogenase (WP_011543503, ldLDH) coding sequence derived from Lactobacillus delbrueckii was obtained from the NCBI database by gene mining. LdLDH was expressed and purified in Escherichia coli, and its enzyme activity, kinetic parameters, optimum temperature, and pH were characterized. Furthermore, stabilizers, including sugars, polyols, amino acids, certain salts, proteins, and polymers, were screened to improve stability of ldLDH during freeze-drying and storage.
Finally, a kit based on ldLDH was tested to determine whether the enzyme had potential clinical applications. The results showed that ldLDH had a specific activity of 1,864 U/mg, Km value of 1.34 mM, optimal reaction temperature of 55°C, and an optimal pH between 7.0 and 7.5. When sucrose or asparagine was used as a stabilizer, freeze-dried ldLDH remained stable at 37°C for > 2 months without significant loss of enzymatic activity. These results indicated that ldLDH possesses high activity and stability. Test results using the ALT assay kit prepared with ldLDH were consistent with those of commercial kits, with a relative deviation <5%. These results indicated that ldLDH met the primary requirements for ALT assays, laying a foundation for the development of new ALT kits with potential clinical applications.
Compatibility of a novel filter paper-based bio-safe sputum transport kit with line probe assay for diagnosing drug-resistant tuberculosis: a single-site evaluation study
Near-patient access to appropriate tests is a major obstacle for the efficient diagnosis of tuberculosis (TB) and associated drug resistance.
We recently developed the “TB Concentration & Transport” kit for bio-safe, ambient-temperature transportation of dried sputum on Trans-Filter, and the “TB DNA Extraction” kit for DNA extraction from Trans-Filter for determining drug resistance by DNA sequencing. In the present study, we evaluated the compatibility of Kit-extracted DNA with Hain’s line probe assays (LPAs), which are endorsed by National TB programmes for the detection of drug resistance in sputum collected from presumptive multidrug-resistant TB patients (n=207).
Trans-Filter-extracted DNA was seamlessly integrated with the LPA protocol (Kit-LPA). The sensitivity of Kit-LPA for determining drug resistance was 83.3% for rifampicin (95% CI 52-98%), 77.7% for isoniazid (95% CI 52-94%), 85.7% for fluoroquinolones (95% CI 42-100%) and 66.6% for aminoglycosides (95% CI 9-99%), with a specificity range of 93.7% (95% CI 87-97) to 99.1% (95% CI 95-100) using phenotypic drug susceptibility testing (DST) as a reference standard. A high degree of concordance was noted between results obtained from Kit-LPA and LPA (99% to 100% (κ value: 0.83-1.0)).
This study demonstrates successful integration of our developed kits with LPA. The adoption of these kits across Designated Microscopy Centres in India can potentially overcome the existing challenge of transporting infectious sputum at controlled temperature to centralised testing laboratories and can provide rapid near-patient cost-effective “Universal DST” services to TB subjects residing in remote areas.
Evaluation of a Commercial Culture-Free Neutralization Antibody Detection Kit for Severe Acute Respiratory Syndrome-Related Coronavirus-2 and Comparison With an Antireceptor-Binding Domain Enzyme-Linked Immunosorbent Assay
Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) surrogate neutralization assays that obviate the need for viral culture offer substantial advantages regarding throughput and cost. The cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript) is the first such commercially available assay that detects antibodies that block receptor-binding domain (RBD)/angiotensin-converting enzyme (ACE)-2 interaction. We aimed to evaluate cPass to inform its use and assess its added value compared with anti-RBD enzyme-linked immunosorbent assays (ELISAs).
EZCell? Phagocytosis Assay Kit (Red Zymosan) | ||||
| K398-100 | Biovision | each | 516 EUR | |
EZCell? Phagocytosis Assay Kit (Green Zymosan) | ||||
| K397-100 | Biovision | each | 516 EUR | |
CytoSelect 96-well Phagocytosis Assay (Zymosan) | ||||
| CBA-224 | Cell Biolabs | 96 assays | 866.4 EUR | |
CytoSelect 96-well Phagocytosis Assay (Zymosan) | ||||
| CBA-224-5 | Cell Biolabs | 5 x 96 assays | 3525.6 EUR | |
CytoSelect 96-Well Phagocytosis Assay(Zymosan Substrate), Trial Size | ||||
| CBA-224-T | Cell Biolabs | 20 assays | 463.2 EUR | |
EZCell? Phagocytosis Assay Kit (Red E. coli) | ||||
| K964-100 | Biovision | each | 502.8 EUR | |
Cell Meter™ Fluorimetric Phagocytosis Assay Kit *Red Fluorescence* | ||||
| 21225 | AAT Bioquest | 100 Tests | 367.2 EUR | |
CytoSelect 96-well Phagocytosis Assay (Red Blood Cell) | ||||
| CBA-220 | Cell Biolabs | 96 assays | 762 EUR | |
EZCell? Phagocytosis Assay Kit (Green E. coli) | ||||
| K963-100 | Biovision | each | 516 EUR | |
EZ-Red? Zymosan A Fluorescent Particles | ||||
| M1204-500 | Biovision | each | 411.6 EUR | |
Polycaspase Assay Kit, red | ||||
| KF17300 | Neuromics | 25 Tests | 340.8 EUR | |
Autophagy Assay, Red | ||||
| KF17373 | Neuromics | 50 Tests | 333.6 EUR | |
Zymosan A | ||||
| Z001-1G | TOKU-E | 1 g | 176.4 EUR | |
Zymosan A | ||||
| Z001-250MG | TOKU-E | 250 mg | 79.2 EUR | |
Zymosan A | ||||
| ZB4250 | Bio Basic | 1g | 385.38 EUR | |
Caspase 9 Assay Kit, red | ||||
| KF17302 | Neuromics | 25 Tests | 364.8 EUR | |
CytoSelect 96-Well Phagocytosis Assay (E. coli, Colorimetric Format) | ||||
| CBA-222 | Cell Biolabs | 96 assays | 831.6 EUR | |
Neutral Red Cell Cytotoxicity Assay Kit | ||||
| K447-1000 | Biovision | each | 379.2 EUR | |
CytoX-Red Cell Proliferation/Cytotoxicity Assay Kit | ||||
| OP-0004 | EpiGentek | 10x96 assays | 474.12 EUR | |
Serum reference panels comprising 205 specimens were used to compare cPass to plaque-reduction neutralization test (PRNT) and a pseudotyped lentiviral neutralization (PLV) assay for detection of neutralizing antibodies. We assessed the correlation of cPass with an ELISA detecting anti-RBD immunoglobulin (Ig)G, IgM, and IgA antibodies at a single timepoint and across intervals from onset of symptoms of SARS-CoV-2 infection.
Compared with PRNT-50, cPass sensitivity ranged from 77% to 100% and specificity was 95% to 100%. Sensitivity was also high compared with the pseudotyped lentiviral neutralization assay (93%; 95% confidence interval [CI], 85-97), but specificity was lower (58%; 95% CI, 48-67). Highest agreement between cPass and ELISA was for anti-RBD IgG (r = 0.823). Against the pseudotyped lentiviral neutralization assay, anti-RBD IgG sensitivity (99%; 95% CI, 94-100) was very similar to that of cPass, but overall specificity was lower (37%; 95% CI, 28-47). Against PRNT-50, results of cPass and anti-RBD IgG were nearly identical.