INTRODUCTION
Tuberculosis (TB) remains one of the world’s leading infectious diseases, posing significant health and socio-economic burdens globally. Despite advances in treatment, the effectiveness of TB control largely depends on rapid and accurate diagnosis. Conventional methods such as sputum smear microscopy and culture, while considered standard, often fail to detect early or extrapulmonary TB cases. This study was conducted in Northeastern Iran between 2020 and 2021 to evaluate how many presumptive TB patients may have been missed by these conventional techniques. By incorporating an in-house real-time PCR (qPCR) TaqMan method, the research aimed to assess the sensitivity and specificity of molecular diagnostics compared with traditional methods, ultimately providing insight into more effective strategies for TB detection and management.
METHODS AND STUDY DESIGN
The study followed a cross-sectional design, involving 307 TB-suspected patients who had previously tested negative by Ziehl-Neelsen (ZN) microscopy and culture. An additional control group comprised 21 confirmed TB-positive patients from a referral TB center in Northeastern Iran. All subjects were re-evaluated using an in-house qPCR assay with the TaqMan method. This molecular approach was selected due to its ability to detect Mycobacterium tuberculosis (M.tb) DNA rapidly, even in paucibacillary and extrapulmonary samples. The study emphasized the feasibility of using standardized reagents, making the assay applicable in various resource-limited settings.
RESULTS AND DIAGNOSTIC PERFORMANCE
The qPCR assay successfully detected all TB cases in the positive control group, establishing a sensitivity of 100%. Among the 307 individuals negative by conventional methods, 50 (13.55%) were positive by qPCR, highlighting the considerable diagnostic gap in routine smear and culture. Specificity was calculated at 83.7%, demonstrating reliable accuracy. Importantly, the findings suggested that a significant proportion of TB cases remain undetected when relying solely on conventional diagnostic approaches.
SAMPLE TYPE AND FAILURE RATES
The study further analyzed failure rates across different sample types. Notably, urine samples showed the highest failure rates in conventional methods, as none tested positive by smear or culture, while six of 20 (30%) were identified as positive by qPCR. In sputum samples, although smear and culture were more effective, qPCR still detected nine additional cases out of 53, proving its superior sensitivity. Interestingly, one of 61 unculturable samples also tested positive with qPCR, reinforcing the utility of molecular diagnostics in challenging sample conditions. These findings indicate that extrapulmonary TB diagnosis, particularly using urine and cerebrospinal fluid (CSF), could be significantly enhanced through qPCR.
CLINICAL AND PUBLIC HEALTH IMPLICATIONS
The results of this study highlight the importance of integrating molecular diagnostics into TB control programs, especially in high-burden regions. Since conventional smear and culture methods can miss a considerable number of cases, patients may go untreated, contributing to continued transmission. Early and accurate diagnosis using qPCR could substantially reduce diagnostic delays, improve treatment outcomes, and prevent disease spread. This approach is particularly valuable in extrapulmonary TB cases, where sample limitations often hinder diagnosis. Thus, molecular methods should complement, rather than replace, traditional diagnostics for a comprehensive TB detection strategy.
CONCLUSIONS AND FUTURE DIRECTIONS
In-house qPCR using the TaqMan method proved to be a practical, feasible, and time-saving diagnostic tool for TB-suspected patients, particularly when conventional methods fail. With 100% sensitivity and acceptable specificity, it offers strong potential for routine use in diagnostic laboratories. Future research should focus on expanding sample size, standardizing protocols, and conducting cost-effectiveness analyses to support broader implementation. Moreover, integrating molecular diagnostics into national TB programs could play a pivotal role in achieving global TB control targets and reducing missed diagnoses in resource-constrained regions.
🔗 Visit: https://infectious-diseases-conferences.pencis.com
🏆 Nominate Now: https://infectious-diseases-conferences.pencis.com/award-nomination/ ecategory=Awards&rcategory=Awardee
📝 Registration Page: https://infectious-diseases-conferences.pencis.com/award-registration/
📩 Contact us: infectioussupport@pencis.com
Hashtags
#TuberculosisResearch, #PCRDiagnostics, #MolecularBiology, #TaqManAssay, #qPCRMethod, #TBDetection, #ClinicalMicrobiology, #TBPrevention, #Epidemiology, #InfectiousDiseases, #GlobalHealth, #MedicalDiagnostics, #LaboratoryMedicine, #PublicHealthResearch, #SmearMicroscopy, #CultureMethod, #MolecularDiagnostics, #TBControl, #HealthcareInnovation, #IranResearch,
No comments:
Post a Comment