NEWER METHODS IN DIAGNOSIS OF LYMPH NODE TUBERCULOSIS - UTILITY OF Xpert MTB/RIF
Dr.T.V.Rao MD
A topic for Post graduates in Microbiology, Pathology and Medicine Lymph nodes are one of the preferred sites for Infection with tuberculosis many surgeons expressed at least 1 or 2 patients present with lymphadenopathy ( majority Cervical regions ) Not to b forget the tuberculosis continues to be most important cause of cervical lymph nodes enlargement , and it is a dictum the surgeons wish to investigate for tuberculosis, The traditional methods of FNAC for cytology and biopsy of lymph nodes for detection of AF,B most pathologists express the suggestion on histopathological examinations, For histology/cytology in case of “Probable TB”, a specimen was positive if the presence of caseation necrosis and epithelioid granulomas was reported. stood the test of time since the onset of AIDS many pathology departments are testing for identification of Acid fast bacilli , the microbiology departments do get for Microscopy culturing, the procedure is undermined by many technical difficulties and lack of dedicated staff, and lacking proper decontamination procedures made many cultures being contaminated with careless processing lacking supervising by Medical Microbiologists, and we have lost the a very valuable specimens, and frequent reporting contamination by Microbiologists many clinicians stop sending the specimen in Microbiology departments, I have to say my frank opinion in a service of 3 decades I have seen 2 to 3 technicians mind their work sincerity and decontamination was the greatest step and neutralization of decontaminating agents was to bring down the ph. If taken care results are excellent, and the growth was demonstrable on LJ medium rapid growers and atypical bacteria are still difficult to identify by Biochemical methods are difficult and kills the valuable time of technical staff Certainly the above said procedures are getting obsolete.
Current trends WHO RECOMMENDATIONS - The WHO has evaluated the matters of the past and traditional methods and made the new protocols
WHO has issued policy recommendations for the use of Xpert MTB/RIF in the diagnosis of extra pulmonary TB and rifampicin resistance detection
• Xpert MTB/RIF should be used in preference to conventional microscopy and culture as the initial diagnostic test in testing cerebrospinal fluid specimens from patients presumed to have TB meningitis (strong recommendation given the urgency of rapid diagnosis, very low quality of evidence);
• Xpert MTB/RIF may be used as a replacement test for usual practice (including conventional microscopy, culture, and/or histopathology) for testing of specific on-respiratory specimens (lymph nodes and other tissues) from patients presumed to have extra pulmonary TB (conditional recommendation, very low quality of evidence).
The World Health Organization (WHO) has endorsed the Xpert MTB/RIF assay as a replacement for sputum smear microscopy. For the diagnosis of patients presumed to have extra pulmonary TB, Xpert MTB/RIF may be used as a replacement test for usual practice (including conventional microscopy, culture, and/or histology) for testing of specific non-respiratory specimens (lymph nodes and other tissues)
This multi functional diagnostic platform is an automated, closed system that performs real-time PCR and can be used by operators with minimal technical expertise, enabling for the diagnosis of TB and simultaneous assessment of RIF resistance to be completed within 2 h
Preparation of Lymph nodes and other tissues (for Xpert MTB/RIF only) is propriety needs the dedicated man power to handle the matter and in biosafe environments if is advisable to send the specimen to the dedicated laboratories with committed manpower and biosafety consideration.
It truly helps the pathologists, microbiologists and physicians as the possibility of tuberculosis is ruled out and can consider the other possibilities for lymphadenopathy , not forgetting malignancies
yet the clinical acumen of physicians remains a necessity for the wise use of any new diagnostic test. Careful application of these new diagnostic tools should improve clinicians' ability to deliver timely, cost-effective care to patients with suspected EPT throughout the world, an approach that future studies should systematically evaluate.
Caution - These recommendations do not apply to stool, urine or blood, given the lack of data on the utility of Xpert MTB/RIF on these specimens
NOTE- Unresolved issues continue with diagnosis of Atypical mycobacterium many reference laboratories still use the traditional methods supported with.use of Xpert MTB/RIF
Reference and Adopted Form Standard Operating Procedure (SOP)Specimen processing of CSF, lymph nodes and other tissues for Xpert MTB/RIF and WHO Resources
T V Rao MD Freelance Reporter on Infectious diseases formulated online teaching portals on Infectious diseases
Dr.T.V.Rao MD
A topic for Post graduates in Microbiology, Pathology and Medicine Lymph nodes are one of the preferred sites for Infection with tuberculosis many surgeons expressed at least 1 or 2 patients present with lymphadenopathy ( majority Cervical regions ) Not to b forget the tuberculosis continues to be most important cause of cervical lymph nodes enlargement , and it is a dictum the surgeons wish to investigate for tuberculosis, The traditional methods of FNAC for cytology and biopsy of lymph nodes for detection of AF,B most pathologists express the suggestion on histopathological examinations, For histology/cytology in case of “Probable TB”, a specimen was positive if the presence of caseation necrosis and epithelioid granulomas was reported. stood the test of time since the onset of AIDS many pathology departments are testing for identification of Acid fast bacilli , the microbiology departments do get for Microscopy culturing, the procedure is undermined by many technical difficulties and lack of dedicated staff, and lacking proper decontamination procedures made many cultures being contaminated with careless processing lacking supervising by Medical Microbiologists, and we have lost the a very valuable specimens, and frequent reporting contamination by Microbiologists many clinicians stop sending the specimen in Microbiology departments, I have to say my frank opinion in a service of 3 decades I have seen 2 to 3 technicians mind their work sincerity and decontamination was the greatest step and neutralization of decontaminating agents was to bring down the ph. If taken care results are excellent, and the growth was demonstrable on LJ medium rapid growers and atypical bacteria are still difficult to identify by Biochemical methods are difficult and kills the valuable time of technical staff Certainly the above said procedures are getting obsolete.
Current trends WHO RECOMMENDATIONS - The WHO has evaluated the matters of the past and traditional methods and made the new protocols
WHO has issued policy recommendations for the use of Xpert MTB/RIF in the diagnosis of extra pulmonary TB and rifampicin resistance detection
• Xpert MTB/RIF should be used in preference to conventional microscopy and culture as the initial diagnostic test in testing cerebrospinal fluid specimens from patients presumed to have TB meningitis (strong recommendation given the urgency of rapid diagnosis, very low quality of evidence);
• Xpert MTB/RIF may be used as a replacement test for usual practice (including conventional microscopy, culture, and/or histopathology) for testing of specific on-respiratory specimens (lymph nodes and other tissues) from patients presumed to have extra pulmonary TB (conditional recommendation, very low quality of evidence).
The World Health Organization (WHO) has endorsed the Xpert MTB/RIF assay as a replacement for sputum smear microscopy. For the diagnosis of patients presumed to have extra pulmonary TB, Xpert MTB/RIF may be used as a replacement test for usual practice (including conventional microscopy, culture, and/or histology) for testing of specific non-respiratory specimens (lymph nodes and other tissues)
This multi functional diagnostic platform is an automated, closed system that performs real-time PCR and can be used by operators with minimal technical expertise, enabling for the diagnosis of TB and simultaneous assessment of RIF resistance to be completed within 2 h
Preparation of Lymph nodes and other tissues (for Xpert MTB/RIF only) is propriety needs the dedicated man power to handle the matter and in biosafe environments if is advisable to send the specimen to the dedicated laboratories with committed manpower and biosafety consideration.
It truly helps the pathologists, microbiologists and physicians as the possibility of tuberculosis is ruled out and can consider the other possibilities for lymphadenopathy , not forgetting malignancies
yet the clinical acumen of physicians remains a necessity for the wise use of any new diagnostic test. Careful application of these new diagnostic tools should improve clinicians' ability to deliver timely, cost-effective care to patients with suspected EPT throughout the world, an approach that future studies should systematically evaluate.
Caution - These recommendations do not apply to stool, urine or blood, given the lack of data on the utility of Xpert MTB/RIF on these specimens
NOTE- Unresolved issues continue with diagnosis of Atypical mycobacterium many reference laboratories still use the traditional methods supported with.use of Xpert MTB/RIF
Reference and Adopted Form Standard Operating Procedure (SOP)Specimen processing of CSF, lymph nodes and other tissues for Xpert MTB/RIF and WHO Resources
T V Rao MD Freelance Reporter on Infectious diseases formulated online teaching portals on Infectious diseases
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