Evaluating the Commutability of Reference Materials for α-Fetoprotein: Accurate Value Assignment With Multiple Systems and Trueness Verification.

Background: The accurate measurement of α-fetoprotein (AFP) is critical for clinical diagnosis. However, different AFP immunoassays may yield different results. Appropriate AFP reference materials (RMs) were selected and assigned accurate values for applications with external quality assessment (EQA) programs to standardize AFP measurements. Methods: Forty individual clinical samples and six different concentrations of candidate RMs (Can-RMs, L1-L6) were prepared by the Beijing Center for Clinical Laboratories. The Can-RMs were assigned target values by performing five immunoassays, using WHO International Standard 72/225 as a calibrator, and sent to 45 clinical laboratories in Beijing for AFP measurements. The commutability of all RMs was assessed based on CLSI and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) approaches. Analytical performance was assessed for compliance based on accuracy (total error, TE), trueness (bias), and precision (CV). Results: The Can-RMs were commutable for all immunoassays using the CLSI approach and for 6 of 10 assay combinations using the IFCC approach. RMs diluted in WHO RM 72/225 were commutable among all assays with the CLSI approach, except for serum matrix (Autolumo vs. Roche analyzer) and diluted water matrix (Abbott vs. Roche/Mindray analyzer), whereas some inconclusive and non-commutable results were found using the IFCC approach. The average pass rates based on the TE, bias, and CV were 91%, 81%, and 95%, respectively. Conclusions: The commutability of the RMs differed between both evaluation approaches. The Can-RMs exhibited good commutability with the CLSI approach, suggesting their suitability for use with that approach as commutable EQA materials with assigned values and for monitoring the performance of AFP measurements.

Joint WHO/EDQM Collaborative study for the establishment of WHO 3rd International Standard and Ph. Eur. Biological Reference Preparation for Prekallikrein activator in albumin batch 7.

An international collaborative study was jointly organised by the World Health Organization (WHO) and the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish the WHO 3rd International Standard (IS) for Prekallikrein activator (PKA) and European Pharmacopoeia (Ph. Eur.) PKA in albumin Biological Reference Preparation (BRP) batch 7. Twenty-six laboratories took part in the study to calibrate these replacement batches, as well as an additional reserve batch for the WHO IS, against the current WHO 2nd IS for PKA (02/168). Ph. Eur. PKA in albumin BRP batch 6 was also included to evaluate the continuity of the consecutive batches of BRP. The centrally calculated overall Huber's means based on the results from laboratories with at least two valid assays were 29.6 and 29.6 IU/ampoule for the candidate WHO 3rd IS (Sample A) and reserve batch (Sample B), and were 38.4 and 37.0 IU/vial for the current BRP batch 6 (Sample C) and the candidate BRP batch 7 (Sample D). The intra-laboratory variation expressed as coefficient of variation (CV) ranged between 1.4 and 16.6 %. The inter-laboratory variation expressed as CV based on Huber's means ranged between 4.4 and 5.4 %. The Huber's mean activity of Sample D against Sample C was 36.6 IU/vial with a CV of 1.7 %. These results confirm the good continuity of the consecutive batches of BRP. Based on the results of this study, it is recommended to establish Sample A as the WHO 3rd IS for PKA with an assigned potency of 30 IU/ampoule and Sample D as the Ph. Eur. PKA in albumin BRP batch 7 with an assigned potency of 37 IU/vial. Sample B is intended to be kept as a future reserve replacement WHO IS.

Update on Non-Interchangeability of Botulinum Neurotoxin Products.

The growing use of botulinum neurotoxins (BoNTs) for medical and aesthetic purposes has led to the development and marketing of an increasing number of BoNT products. Given that BoNTs are biological medications, their characteristics are heavily influenced by their manufacturing methods, leading to unique products with distinct clinical characteristics. The manufacturing and formulation processes for each BoNT are proprietary, including the potency determination of reference standards and other features of the assays used to measure unit potency. As a result of these differences, units of BoNT products are not interchangeable or convertible using dose ratios. The intrinsic, product-level differences among BoNTs are compounded by differences in the injected tissues, which are innervated by different nerve fiber types (e.g., motor, sensory, and/or autonomic nerves) and require unique dosing and injection sites that are particularly evident when treating complex therapeutic and aesthetic conditions. It is also difficult to compare across studies due to inherent differences in patient populations and trial methods, necessitating attention to study details underlying each outcome reported. Ultimately, each BoNT possesses a unique clinical profile for which unit doses and injection paradigms must be determined individually for each indication. This practice will help minimize unexpected adverse events and maximize efficacy, duration, and patient satisfaction. With this approach, BoNT is poised to continue as a unique tool for achieving individual goals for an increasing number of medical and aesthetic indications.

Reference Standards for C-Peptide in Korean Population: A Korean Endocrine Hormone Reference Standard Data Center Study.

BACKGRUOUND: The Korean Endocrine Hormone Reference Standard Data Center (KEHRS DC) has created reference standards (RSs) for endocrine hormones since 2020. This study is the first of its kind, wherein the KEHRS DC established RSs for serum Cpeptide levels in a healthy Korean population. METHODS: Healthy Korean adults were recruited from May 2021 to September 2023. After excluding participants according to our criteria, serum samples were collected; each participant could then choose between fasting glucose only or fasting glucose plus an oral glucose tolerance test (OGTT). If their sample showed high glucose (≥100 mg/dL) or hemoglobin A1c (HbA1c) (≥5.70%), their C-peptide levels were excluded from analyzing the RSs. RESULTS: A total of 1,532 participants were recruited; however, only the data of 1,050 participants were analyzed after excluding those whose samples showed hyperglycemia or high HbA1c. Post-30-minute OGTT data from 342 subjects and post-120-minute OGTT data from 351 subjects were used. The means±2 standard deviations and expanded uncertainties of fasting, post-30-minute and 120-minute OGTT C-peptide levels were 1.26±0.82 and 0.34-3.18, 4.74±3.57 and 1.14-8.33, and 4.85±3.58 and 1.25-8.34 ng/mL, respectively. Serum C-peptide levels correlated with obesity, serum glucose levels, and HbA1c levels. CONCLUSION: The RSs for serum C-peptide levels established in this study are expected to be useful in both clinical and related fields.

The LEADING Guideline: Reporting Standards for Expert Panel, Best-Estimate Diagnosis, and Longitudinal Expert All Data (LEAD) Studies.

Accurate assessments of symptoms and diagnoses are essential for health research and clinical practice but face many challenges. The absence of a single error-free measure is currently addressed by assessment methods involving experts reviewing several sources of information to achieve a more accurate or best-estimate assessment. Three bodies of work spanning medicine, psychiatry, and psychology propose similar assessment methods: The Expert Panel, the Best-Estimate Diagnosis, and the Longitudinal Expert All Data (LEAD). However, the quality of such best-estimate assessments is typically very difficult to evaluate due to poor reporting of the assessment methods and when it is reported, the reporting quality varies substantially. Here we tackle this gap by developing reporting guidelines for such studies, using a four-stage approach: 1) drafting reporting standards accompanied by rationales and empirical evidence, which were further developed with a patient organization for depression, 2) incorporating expert feedback through a two-round Delphi procedure, 3) refining the guideline based on an expert consensus meeting, and 4) testing the guideline by i) having two researchers test it and ii) using it to examine the extent previously published articles report the standards. The last step also demonstrates the need for the guideline: 18 to 58% (Mean = 33%) of the standards were not reported across fifteen randomly selected studies. The LEADING guideline comprises 20 reporting standards related to four groups: The Longitudinal design; the Appropriate data; the Evaluation - experts, materials, and procedures; and the Validity group. We hope that the LEADING guideline will be useful in assisting researchers in planning, reporting, and evaluating research aiming to achieve best-estimate assessments.

Evaluation of Loop-Mediated Isothermal Amplification Assay in Diagnosing Tuberculous Meningitis.

BACKGROUND: Resource-limited settings like India need a simple, quick, and temperature-independent point-of-care diagnostic test that can diagnose tuberculous meningitis (TBM) at the earliest. METHODS: A prospective study was carried out at a tertiary care center in North India wherein 50 subjects suspected of TBM were recruited and followed up for six months between January 2019 and December 2020. The aim was to evaluate the performance of loop-mediated isothermal amplification (TB-LAMP) in diagnosing TBM as compared to a composite reference standard (CRS), mycobacteria growth indicator tube 960 (MGIT 960) culture, and GeneXpert®. RESULTS: Out of 50 patients, 32 were TBM cases (64%), and 18 were non-TBM cases (36%). The sensitivity of TB-LAMP and GeneXpert® for TBM diagnosis against CRS was 53% (17/32) for both, and the specificity was 78% (14/18) and 89% (16/18), respectively. On comparing TB-LAMP against GeneXpert® for TBM diagnosis, the two methods had almost perfect agreement (Cohen's kappa=0.83) with statistical significance (p<0.001). CONCLUSION: The performance of TB-LAMP assay is comparable to GeneXpert® in diagnosing TBM, and it may be used as a substitute for CSF GeneXpert® in resource-limited settings.

Diagnosing adult and pediatric extrapulmonary tuberculosis by MPT64 antigen detection with immunohistochemistry and immunocytochemistry using reproduced polyclonal antibodies.

Diagnosing extrapulmonary tuberculosis (EPTB) is challenging. Immunohistochemistry or immunocytochemistry has been used to diagnose tuberculosis (TB) by detection of MPT64 antigen from various extrapulmonary specimens and has shown good diagnostic performance in our previous studies. The test can distinguish between disease caused by Mycobacterium tuberculosis (Mtb) complex and nontuberculous mycobacteria and can be applied on formalin-fixed paraffin-embedded tissue. As the antibodies previously used were in limited supply, a new batch of polyclonal antibodies was developed for scale-up and evaluated for the first time in this study. Our aim was to assess the diagnostic accuracy of the MPT64 test with reproduced antibodies in the high burden settings of Pakistan and India. Patients were enrolled prospectively. Samples from suspected sites of infection were collected and subjected to histopathologic and/or cytologic evaluation, routine TB diagnostics, GeneXpert MTB/RIF (Xpert), and the MPT64 antigen detection test. Patients were followed until the end of treatment. Based on a composite reference standard (CRS), 556 patients were categorized as TB cases and 175 as non-TB cases. The MPT64 test performed well on biopsies with a sensitivity and specificity of 94% and 75%, respectively, against a CRS. For cytology samples, the sensitivity was low (36%), whereas the specificity was 81%. Overall, the MPT64 test showed higher sensitivity (73%) than Xpert (38%) and Mtb culture (33%). The test performed equally well in adults and children. We found an additive diagnostic value of the MPT64 test in conjunction with histology and molecular tests, increasing the yield for EPTB. In conclusion, immunochemical staining with MPT64 antibodies improves the diagnosis of EPTB in high burden settings and could be a valuable addition to routine diagnostics.

Selecting a birth weight standard for an indigenous population in a LMIC: A prospective comparative study.

OBJECTIVES: The aim of the present study was to compare birth weight (BW) distribution and proportion of BWs below or above specified percentiles in low-risk singleton pregnancies in healthy South African (SA) women of mixed ancestry with expected values according to four BW references and to determine the physiological factors affecting BW. METHODS: This was an ancillary study of a prospective multinational cohort study, involving 7060 women recruited between August 2007 and January 2015 in two townships of Cape Town, characterized by low socioeconomic status, and high levels of drinking and smoking. Detailed information about maternal and pregnancy characteristics, including harmful exposures, was gathered prospectively, allowing us to select healthy women with uncomplicated pregnancies without any known harmful exposures. In this cohort we compared the median BW and the proportion of BWs P90, 95 and 97 according to four reference standards (INTERGROWTH-21st, customized according to the method described by Mickolajczyk, Fetal Medicine Foundation and revised Fenton reference) with expected values. Appropriate parametric and nonparametric tests were used, and sensitivity analysis was performed for infant sex, first trimester bookings and women of normal body mass index (BMI). Multiple regression was used to explore effects of confounders. Written consent and ethics approval was obtained. RESULTS: The cohort included 739 infants. The INTERGROWTH-21st standard was closest for the actual BW-distribution and categories. Below-expected BW was associated with boys, younger, shorter, leaner women, lower parity and gravidity. Actual BW was significantly influenced by maternal weight, BMI, parity and gestational age. CONCLUSION: Of the four references assessed in this study, the INTERGROWTH-21st standard was closest for the actual BW distribution. Maternal variables significantly influence BW.

Report of a collaborative study to establish the first Indian Pharmacopoeia reference standard for teriparatide.

A collaborative study was conducted to establish the first Indian Pharmacopoeia Reference Standard (IPRS) for teriparatide to be used in quality control testing of marketed products in compliance with the Indian Pharmacopoeia (IP) monograph. The study objective was to evaluate the candidate standard in terms of the WHO International Standard (IS) to assign its content in mg per vial terms. This study involved four laboratories from India and the candidate standard was calibrated against the WHO IS by each participant laboratory using high-performance liquid chromatography (HPLC) assay method per IP monograph. Direct calibration of the candidate standard resulted in an assigned content of 1.02 mg per vial. Based on the study results the candidate standard was judged suitable to serve as the first IPRS for teriparatide for identification and assay by HPLC.

Collaborative study for the establishment of Ph. Eur. Biological Reference Preparation for Human tetanus immunoglobulin batch 2.

This publication describes the outcome of a project to develop a replacement European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for Human tetanus immunoglobulin (TIg) as well as for the World Health Organization (WHO) International Standard (IS) for Tetanus Immunoglobulin, Human. Bulk TIg was kindly provided by a European manufacturer and was used to prepare the candidate standard. The candidate standard was freeze-dried and calibrated in an international collaborative study jointly co-ordinated by the Medicines & Healthcare products Regulatory Agency (MHRA) and the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe). The results of this study show that there was good agreement between laboratories for the potency estimates obtained for the candidate standard relative to the current WHO IS/Ph. Eur. BRP. The study also demonstrated that the candidate standard is suitable for use in Ph. Eur. assays for potency testing of TIg products and there was good agreement in the potency estimates obtained using the different assay methods included in the study. Accelerated degradation studies performed at the MHRA over a period of 4 years suggest that the freeze-dried candidate standard will be very stable. The candidate standard was established as Ph. Eur. BRP for Human tetanus immunoglobulin, batch 2 with an assigned potency of 45 IU/ampoule. The same preparation was also adopted by the WHO Expert Committee on Biological Standardization (ECBS) to serve as the WHO 2nd IS for Tetanus Immunoglobulin, Human (13/240).

A multidimensional strategy for characterization, distinction, and quality control of two Clinopodium medicinal plants.

ETHNOPHARMACOLOGICAL RELEVANCE: Clinopodium chinense Kuntze (CC) and Clinopodium polycephalum (Vaniot) C. Y. Wu & S. J. Hsuan (CP) are both included in the Pharmacopoeia of the People's Republic of China (edition 2020) as the legitimate source of "Duan Xue Liu" (DXL), which is a crucial traditional Chinese medicine used as a clinical remedy for bleeding diseases. However, the differences in plant endogenous metabolites and bioactivities between CC and CP are still unclear. AIM OF THE STUDY: This study aims to provide a scientific basis to investigate the differences between CC and CP ensuring the efficient and safe use of DXL. MATERIALS AND METHODS: A multidimensional strategy including plant metabolomics, digital reference standard (DRS) analyzer, and biological activities assay was creatively constructed for the characterization, distinction, and quality control of CC and CP. RESULTS: There were apparent differences in the metabolites between CC and CP. 7 compounds contributing to the differences were successfully identified. On that basis, linear calibration using two reference substances (LCTRS) methods was proved as a more accurate and specific quality analysis method for CC and CP. In addition, bioactivity assays showed that both CC and CP exhibited obvious hemostatic activity, while CC showed greater potential to resist inflammation and free radicals. CONCLUSION: In summary, it was the first time to investigate the chemical constituents and bioactivities differences between CC and CP with the help of plant metabolomics, DRS study, and biological activity assays. These two plants were significantly separated in the integrated analysis, suggesting that we should pay attention to the distinction to prevent unexpected risks caused by medicinal materials.

Isolation and characterization of reference standard candidates for cocaine and benzoylecgonine obtained from illicit substances seized.

The area of forensic chemistry has been growing and developing as a line of research due to the high demands of public safety that require increasingly reliable results due to their importance in criminalistics. In this way, the development of new technologies that help this area, whether in the identification and quantification of drugs or the fight against fraud, becomes promising. In this context, the present work explored the production of reference standards from the purification of cocaine/crack samples seized by the Civil Police of the State of Espírito Santo. Cocaine was purified using chromatographic techniques, and benzoylecgonine was synthesized from purified cocaine. All substances were characterized by ultra-high-resolution mass spectrometry and nuclear magnetic resonance. Homogeneity and stability studies were also performed with benzoylecgonine, and the results were evaluated using analysis of variance (ANOVA). Cocaine and benzoylecgonine showed purities of 98.37% and 96.34%, respectively. The homogeneity of the batch, short-term stability, and other parameters were also evaluated, which together indicate this proposal as promising in the development of reference standards for drugs of abuse from samples seized by the Brazilian forensic police.

[Route to the Adoption of Quantitative NMR in the Japanese Pharmacopoeia].

Quantitative NMR (qNMR) is employed to determine the purity of reagents used as standards for HPLC quantification in the Japanese Pharmacopoeia (JP) and has become recognized as a new absolute quantification method in various fields such as pharmaceuticals, foods, and food additives. This report outlines how and why qNMR has been adopted as an official method in the JP and introduces its progression from JP16 to JP18. The results of a survey of companies in the Japan Pharmaceutical Manufacturers' Association regarding how and when to use qNMR from development to manufacturing stages are introduced. The issues involved in the expansion of the use of qNMR in the field of chemical pharmaceuticals in 2017 are discussed and how these were resolved.

Point of care ultrasound combined with CTS-6 to diagnose idiopathic carpal tunnel syndrome.

BACKGROUND: This study aimed to demonstrate the effectiveness of our new diagnostic chart using point of care ultrasound combined with CTS-6 for diagnosing idiopathic carpal tunnel syndrome. METHODS: We conducted a retrospective analysis of the data of patients who visited our department and received point of care ultrasound combined with CTS-6 from 2020 to 2023. Data regarding age, sex, initial and final diagnosis, cross-sectional area of the median nerve, CTS-6 score, and electrodiagnostic severity were obtained and statistically analyzed. RESULTS: Of the 177 wrists included in our study, 138 (78 %) were diagnosed with carpal tunnel syndrome, while 39 (22 %) were not (non-carpal tunnel syndrome). With our diagnostic method, 127 wrists (72 %) were diagnosed initially with carpal tunnel syndrome, 23 wrists (13 %) with non-carpal tunnel syndrome, and the rest 27 wrists (15 %) as borderline. Our initial diagnoses of carpal tunnel syndrome and non-carpal tunnel syndrome were maintained in all cases except for two. Cross-sectional area, CTS-6 score, and electrodiagnostic severity showed a positive correlation. A post hoc analysis showed that the new scoring system (CTS-6 score + 2 × cross-sectional area) with a cutoff value of 31.25 points showed a sensitivity as high as 95 % and a specificity of 100 %. CONCLUSIONS: Our findings suggest that most suspected idiopathic carpal tunnel syndrome cases can be diagnosed correctly using the diagnostic chart. Although additional tools, including electrodiagnostic studies, may be needed for borderline cases, the use of point of care ultrasound combined with CTS-6 may be a recommendable first-line confirmatory test because point of care ultrasound and CTS-6 could be complementary tools, and this chart may be especially beneficial for atypical or outlier cases. LEVEL OF EVIDENCE: Diagnostic III.

Reproducible Reporting of the Collection and Evaluation of Annotations for Artificial Intelligence Models.

This work puts forth and demonstrates the utility of a reporting framework for collecting and evaluating annotations of medical images used for training and testing artificial intelligence (AI) models in assisting detection and diagnosis. AI has unique reporting requirements, as shown by the AI extensions to the Consolidated Standards of Reporting Trials (CONSORT) and Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklists and the proposed AI extensions to the Standards for Reporting Diagnostic Accuracy (STARD) and Transparent Reporting of a Multivariable Prediction model for Individual Prognosis or Diagnosis (TRIPOD) checklists. AI for detection and/or diagnostic image analysis requires complete, reproducible, and transparent reporting of the annotations and metadata used in training and testing data sets. In an earlier work by other researchers, an annotation workflow and quality checklist for computational pathology annotations were proposed. In this manuscript, we operationalize this workflow into an evaluable quality checklist that applies to any reader-interpreted medical images, and we demonstrate its use for an annotation effort in digital pathology. We refer to this quality framework as the Collection and Evaluation of Annotations for Reproducible Reporting of Artificial Intelligence (CLEARR-AI).

Collaborative study for the establishment of Ph. Eur. Biological Reference Preparation for Human tetanus immunoglobulin batch 2.

This publication describes the outcome of a project to develop a replacement European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for Human tetanus immunoglobulin (TIg) as well as for the World Health Organization (WHO) International Standard (IS) for Tetanus Immunoglobulin, Human. Bulk TIg was kindly provided by a European manufacturer and was used to prepare the candidate standard. The candidate standard was freeze-dried and calibrated in an international collaborative study jointly co-ordinated by the Medicines & Healthcare products Regulatory Agency (MHRA) and the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe). The results of this study show that there was good agreement between laboratories for the potency estimates obtained for the candidate standard relative to the current WHO IS/Ph. Eur. BRP. The study also demonstrated that the candidate standard is suitable for use in Ph. Eur. assays for potency testing of TIg products and there was good agreement in the potency estimates obtained using the different assay methods included in the study. Accelerated degradation studies performed at the MHRA over a period of 4 years suggest that the freeze-dried candidate standard will be very stable. The candidate standard was established as Ph. Eur. BRP for Human tetanus immunoglobulin, batch 2 with an assigned potency of 45 IU/ampoule. The same preparation was also adopted by the WHO Expert Committee on Biological Standardization (ECBS) to serve as the WHO 2nd IS for Tetanus Immunoglobulin, Human (13/240).

Preparation of the first national reference standard for determination of HEK293 cell DNA content / 中国生物制品学杂志

@#Objective To prepare a national reference standard for the quantification of HEK293 cell DNA content,so as to provide a support for the determination of residual DNA in HEK293 cells in the industry.Methods HEK293 cell DNA prepared using Genomic-tip 500/G and genomic DNA purification reagents was used as source materials,and the purity and content were assessed using ultraviolet spectrophotometry and agarose gel electrophoresis.After dilution to approximately 100 ng/μL,the DNA was aliquoted at 160 μL/tube.Five different laboratories were organized for collaborative calibration by using ultraviolet spectrophotometry, and the stability and applicability were evaluated.Results The HEK293 cell DNA national reference standard exhibited A_(260)/A_(280) ratios between 1.8 and 2.0 and displayed a single band on electrophoresis,meeting the specified criteria.Collaborative calibration across five laboratories yielded 78 valid data points with an average content of 104.8 ng/μL,a relative standard deviation(RSD) of 4.2%.The 95% confidence interval for the mean was 103.8—105.8 ng/μL,and the 95% reference range for single measurements was 96.0—113.6 ng/μL.The average confidence limit rate was 1.0%,and the recommended storage condition was-80 ℃.Applicability studies were conducted using two different models of fluorescence quantitative PCR instruments.The reference standard exhibited good applicability within the range of 0.3—3 000 pg/reaction,with amplification efficiencies of 101% and 95%,and R~2 values of 0.999 2 and 0.999 5 for the standard curves,respectively.Conclusion This batch of HEK293 cell DNA national reference standard meets all required specifications and can be utilized as a national reference standard for fluorescence quantitative PCR detection,with a certified content of 104.8 ng/μL,assigned batch number 270039-202301.

Evaluation of kit-based loop-mediated isothermal amplification (TB-LAMP) assay in the diagnosis of tubercular lymphadenitis.

Background: The rapid and accurate diagnosis of tubercular lymphadenitis remains a challenging task today. The World Health Organization (WHO) endorsed the LoopAMP MTBC kit (TB-LAMP) as a replacement for sputum smear microscopy in the diagnosis of pulmonary tuberculosis (PTB). However, no prospective diagnostic accuracy study of TB-LAMP for tubercular lymphadenitis in adults has been performed yet. The current study evaluated the diagnostic performance of TB-LAMP in tubercular lymphadenitis (LNTB). Methods: In a prospective observational study conducted at a tertiary care hospital in India, 90 subjects (age >18 years) suspected of LNTB were recruited consecutively and followed up for 6 months between January 2019 and December 2020. Samples were processed for microscopy, culture, GeneXpert, histopathology and TB-LAMP. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of TB-LAMP against the composite reference standard (CRS) and culture were determined. Results: TB-LAMP showed a sensitivity of 83.78 % (95 % CI, 73.76-90.47) and a specificity of 81.25 % (95 % CI, 56.99-93.41), respectively, against the CRS. The PPV and NPV were 95.38 % (95 % CI, 87.29-98.42) and 52.00 % (95 % CI, 33.50-69.97), respectively. TB-LAMP showed a sensitivity of 88.89 % (95 % CI, 71.94-96.15) and a specificity of 36.17 % (95 % CI, 23.97-50.46), respectively, against culture. The PPV and NPV were 44.44 % (95 % CI, 32-57.62) and 85 % (95 % CI, 63.96-94.76), respectively. Conclusion: TB-LAMP can be used instead of conventional microscopy for the diagnosis of TB in lymph node specimens at primary healthcare centres. It provides rapid and cost-effective diagnosis of LNTB in resource-limited settings due to good sensitivity and NPV.