Improving diagnosis of tuberculous lymphadenitis by combination of cytomorphology and MPT64 immunostaining on cell blocks from the fine needle aspirates

Extrapulmonary Comparisons Between Mycobacterium Tuberculosis and Non-Tuberculous Mycobacteria: From Manifestations and Diagnosis to Treatment

The incidence of tuberculosis (TB) and non-tuberculous mycobacteria (NTM) diseases and the number of deaths from these diseases are steadily increasing worldwide. However, the pathologic diagnosis of NTM disease is similar to that of tuberculosis, and it is often difficult to distinguish between the two, which can lead to misdiagnosis and treatment aversion. Therefore, differentiation between the two can help in accurate diagnosis and treatment planning. This review compares the presentation, diagnosis, and treatment of common extrapulmonary sites of involvement in tuberculosis and non-tuberculous mycobacterial disease.

Performance of conventional laboratory tests and Xpert MTB/RIF in the diagnosis of tuberculosis

The laboratory diagnosis of tuberculosis (TB) represents a continuous challenge due to the variability and complexity of the required clinical samples. Although molecular technologies have considerably improved diagnostic accuracy, their combined use with traditional methods like microscopy and bacterial culture remains a subject of debate. This study aims to compare the performance of microscopy, bacterial culture on Löwenstein-Jensen medium, and the molecular Xpert MTB/RIF test in diagnosing pulmonary and extrapulmonary TB. In this retrospective study, conducted over a period from January 2016 to January 2023, data were collected from pulmonary TB and extrapulmonary TB samples of patients hospitalized in the pneumonology departments of the Bihor County Emergency Hospital. The study included 1796 patients, of whom 85.2% had samples collected from the respiratory tract. The variability of sensitivity and specificity depending on the type of sample indicates the need for a differentiated approach in diagnosis. The results show that the Xpert MTB/RIF test detected a higher number of positive cases (16%) compared to microscopy (9%) and bacterial culture (15%). Statistical analysis revealed a high sensitivity and specificity of Xpert MTB/RIF, suggesting superior accuracy compared to traditional methods. Our conclusions underline the importance of the Xpert MTB/RIF as a valuable tool in the diagnosis of TB, but it is recommended to use it in combination with other methods to ensure a complete and efficient diagnosis.

A retrospective study of extrapulmonary tuberculosis in the Khuzestan province of southwest Iran between 2002 and 2023

BACKGROUND

Worldwide, tuberculosis (TB) is among the most common causes of death. To our knowledge, there has been no study showing the prevalence of EPTB in Khuzestan province. Therefore, the objective of this research was to investigate the prevalence of EPTB in patients with or without pulmonary TB in different cities of Khuzestan province from 2002 to 2023. Additionally, the correlation between patient's gender, and age groups with the disease was also investigated.

METHODS

In this retrospective study, the existing records in Tuberculosis Regional Reference Laboratory of Khuzestan province related to patients were used. The research was carried out by investigating the archive information in 19 years (from 1st January 2002 to December 30, 2023). All confirmed cases of EPTB and simultaneous EPTB and PTB, based on laboratory results and medical examination were included in the study. Patients with incomplete information and military TB were excluded from the study. Information collected from patients includes age, gender, involved organ, place of residence, and year of disease.

RESULTS

A total of 12,900 EPTB-related medical records were extracted from Tuberculosis Regional Reference Laboratories in southwest Iran, Ahvaz. After excluding records, 12,836 clinically diagnosed or laboratory-confirmed tuberculosis patients were included in this study, including 5991 patients with simultaneous PTB and EPTB, and 6845 patients with EPTB only. The mean age of male EPTB patients was 37.5 years (SD ± 14.6), while the mean age of male patients with simultaneous PTB and EPTB was 45.8 years (SD ± 15.3). The mean age of female patients with EPTB only, and with simultaneous PTB and EPTB was 31.2 years (SD ± 12.6), and 31.5 years respectively.

DISCUSSION

tuberculosis is a systemic disease with different clinical manifestations. This study described different epidemiologic patterns of concurrent EPTB. The proportion of different types of EPTB was simultaneously determined for a group of hospitalized patients and shown to be different with gender and age. This study will likely increase clinicians' awareness of the disease and help them better address diagnostic challenges and improve treatment outcomes for patients with EPTB.

Principles of Analytic Validation of Immunohistochemical Assays: Guideline Update

CONTEXT.—

In 2014, the College of American Pathologists developed an evidence-based guideline to address analytic validation of immunohistochemical assays. Fourteen recommendations were offered. Per the National Academy of Medicine standards for developing trustworthy guidelines, guidelines should be updated when new evidence suggests modifications.

OBJECTIVE.—

To assess evidence published since the release of the original guideline and develop updated evidence-based recommendations.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and update the original guideline recommendations using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS.—

Two strong recommendations, 1 conditional recommendation, and 12 good practice statements are offered in this updated guideline. They address analytic validation or verification of predictive and nonpredictive assays, and recommended revalidation procedures following changes in assay conditions.

CONCLUSIONS.—

While many of the original guideline statements remain similar, new recommendations address analytic validation of assays with distinct scoring systems, such as programmed death receptor-1 and analytic verification of US Food and Drug Administration approved/cleared assays; more specific guidance is offered for validating immunohistochemistry performed on cytology specimens.

Diagnostic value of tuberculosis-specific antigens ESAT-6 and CFP10 in lymph node tuberculosis

Objective

To assess the diagnostic value of immunohistochemical (IHC) staining for detecting the tuberculosis-secreted antigens ESAT-6 and CFP10 in lymph node tuberculosis.

Methods

Archived, paraffin-embedded lymph node specimens from 72 patients diagnosed with lymph node tuberculosis and 68 patients with lymphoma were retrospectively collected from the Department of Pathology at the Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan Province, China between January 2016 and March 2023. These specimens were subjected to acid-fast and immunohistochemical staining to compare the effectiveness of these methods, with their sensitivity and specificity evaluated against a comprehensive reference standard.

Results

Acid-fast staining demonstrated a sensitivity of 12.3% and a specificity of 100%. IHC staining for ESAT-6 showed a sensitivity of 87.5% and a specificity of 85.3%, whereas IHC staining for CFP10 exhibited a sensitivity of 75.0% and a specificity of 89.7%.

Conclusion

The study indicates that IHC detection of ESAT-6 and CFP10 in paraffin-embedded lymph node tuberculosis tissues has a markedly higher sensitivity compared to acid-fast staining. Thus, IHC staining may serve as a supplementary diagnostic tool for the pathological evaluation of lymph node tuberculosis.