Combined Tests Improve Tuberculous Meningitis Diagnosis
By LabMedica International staff writers Posted on 21 Feb 2016 |
At present, there is no established laboratory test to diagnose early tuberculous meningitis and cerebrospinal fluid (CSF) culture sensitivity is low in developing countries and it usually takes several weeks to obtain results with this method.
Tuberculous meningitis (TBM), the most severe form of tuberculosis (TB), accounts for 5% to 10% of extrapulmonary TB and 0.5% of systemic TB worldwide. Those who have contracted this disease have a mortality rate of 20% to 41% in developed countries and 44% to 69% in developing countries.
Scientists at Huashan Hospital Fudan University (Shanghai, China) studied a total of 30 patients who were suspected of having TBM, of whom six were clinically diagnosed as having TBM and 24 as probably harboring the disease. These patients included 24 men and six women, aged between 18 and 79 years, with a mean age of 45 years. The diagnostic criteria for TBM were positive acid-fast (AFS) results or positive CSF culture results for Mycobacterium tuberculosis.
After the first admission of each study participant from the TBM and control patient to the hospital, a 1-mL CSF specimen from each via lumbar puncture was collected. The team also collected cerebrospinal fluid from 10 patients in the TBM group on initial visit and at four weeks, to observe changes. A total of 30 individuals with TBM and 39 control individuals without TBM participated in this study. IFN-γ-secreting T cells were detected by ELISPOT, an enzyme-linked immunospot (T-SPOT.TB, Oxford Immunotec International, Abingdon, UK), and cerebrospinal fluid interferon-γ (cIFN-γ) was detected by enzyme-linked immunosorbent assay (ELISA).
The sensitivity and specificity of peripheral-blood T-SPOT.TB testing in the diagnosis of TBM were 70% and 87%, respectively. The area under the receiver operating characteristic (ROC) curve of cIFN-γ (greater than 81.36 pg/mL) for TBM diagnosis was 0.819, and the corresponding sensitivity and specificity were 83% and 85%, respectively. When T-SPOT.TB and cIFN-γ results were positive, the specificity and positive predictive value of TBM diagnosis reached 100%. The consistency is poor between peripheral-blood T-SPOT.TB and cIFN-methods probably due to the factors that could result in false-negative and false-positive results. However, this finding may partially confirm that the combination of these approaches can improve the efficiency of diagnosis of TBM.
The authors concluded that cIFN-γ testing is a rapid, economical, and highly sensitive approach to the diagnosis of TBM. Dynamic observation of cIFN-γ is important for monitoring patients with TBM, a condition that responds well to treatment. Peripheral blood T-SPOT.TB testing for TBM diagnosis is also important. The combination of peripheral blood T-SPOT.TB and cIFN-γ detection can improve overall sensitivity and specificity in the diagnosis of TBM. The study was published on January 4, 2016 in the journal Laboratory Medicine.
Related Links:
Huashan Hospital Fudan University
Oxford Immunotec International
Tuberculous meningitis (TBM), the most severe form of tuberculosis (TB), accounts for 5% to 10% of extrapulmonary TB and 0.5% of systemic TB worldwide. Those who have contracted this disease have a mortality rate of 20% to 41% in developed countries and 44% to 69% in developing countries.
Scientists at Huashan Hospital Fudan University (Shanghai, China) studied a total of 30 patients who were suspected of having TBM, of whom six were clinically diagnosed as having TBM and 24 as probably harboring the disease. These patients included 24 men and six women, aged between 18 and 79 years, with a mean age of 45 years. The diagnostic criteria for TBM were positive acid-fast (AFS) results or positive CSF culture results for Mycobacterium tuberculosis.
After the first admission of each study participant from the TBM and control patient to the hospital, a 1-mL CSF specimen from each via lumbar puncture was collected. The team also collected cerebrospinal fluid from 10 patients in the TBM group on initial visit and at four weeks, to observe changes. A total of 30 individuals with TBM and 39 control individuals without TBM participated in this study. IFN-γ-secreting T cells were detected by ELISPOT, an enzyme-linked immunospot (T-SPOT.TB, Oxford Immunotec International, Abingdon, UK), and cerebrospinal fluid interferon-γ (cIFN-γ) was detected by enzyme-linked immunosorbent assay (ELISA).
The sensitivity and specificity of peripheral-blood T-SPOT.TB testing in the diagnosis of TBM were 70% and 87%, respectively. The area under the receiver operating characteristic (ROC) curve of cIFN-γ (greater than 81.36 pg/mL) for TBM diagnosis was 0.819, and the corresponding sensitivity and specificity were 83% and 85%, respectively. When T-SPOT.TB and cIFN-γ results were positive, the specificity and positive predictive value of TBM diagnosis reached 100%. The consistency is poor between peripheral-blood T-SPOT.TB and cIFN-methods probably due to the factors that could result in false-negative and false-positive results. However, this finding may partially confirm that the combination of these approaches can improve the efficiency of diagnosis of TBM.
The authors concluded that cIFN-γ testing is a rapid, economical, and highly sensitive approach to the diagnosis of TBM. Dynamic observation of cIFN-γ is important for monitoring patients with TBM, a condition that responds well to treatment. Peripheral blood T-SPOT.TB testing for TBM diagnosis is also important. The combination of peripheral blood T-SPOT.TB and cIFN-γ detection can improve overall sensitivity and specificity in the diagnosis of TBM. The study was published on January 4, 2016 in the journal Laboratory Medicine.
Related Links:
Huashan Hospital Fudan University
Oxford Immunotec International
Read the full article by registering today, it's FREE!
Register now for FREE to LabMedica.com and get complete access to news and events that shape the world of Clinical Laboratory Medicine.
- Free digital version edition of LabMedica International sent by email on regular basis
- Free print version of LabMedica International magazine (available only outside USA and Canada).
- Free and unlimited access to back issues of LabMedica International in digital format
- Free LabMedica International Newsletter sent every week containing the latest news
- Free breaking news sent via email
- Free access to Events Calendar
- Free access to LinkXpress new product services
- REGISTRATION IS FREE AND EASY!
Sign in: Registered website members
Sign in: Registered magazine subscribers
Latest Microbiology News
- High-Accuracy Bedside Test to Diagnose Periprosthetic Joint Infection in Five Minutes
- Innovative Diagnostic Approach for Bacterial Infections to Enable Faster and Effective Treatment
- Non-Invasive Stool Test to Diagnose Endometriosis and Help Reduce Disease Progression
- Automated Positive Blood Culture Sample Preparation Platform Designed to Fight Against Sepsis and AMR
- Revolutionary Molecular Culture ID Technology to Transform Bacterial Diagnostics
- New Digital PCR Assays Enable Accurate and Sensitive Detection of Critical Pathogens
- Rapid Diagnostic System to Deliver Same-Shift Antibiotic Susceptibility Test Results
- AST System Delivers Actionable Results for Gram-Negative Bacteria Directly from Positive Blood Cultures
- Ultra-Rapid Culture-Free Sepsis Test Reduces Testing Time from Days to Hours
- New Rapid Method for Determining Virus Infectivity Could Revolutionize Response to Future Pandemics
- Novel Molecular Test to Help Prevent and Control Multi Drug-Resistant Fungal Pathogen in Healthcare Settings
- Innovative C. Difficile Diagnostic Test Provides Both GDH and Toxin Results within 30 Minutes
- Rapid UTI Test Cuts Detection Time from 3 days to 45 Minutes
- POC STI Test Shortens Time from ED Arrival to Test Results
- Integrated Solution Ushers New Era of Automated Tuberculosis Testing
- Automated Sepsis Test System Enables Rapid Diagnosis for Patients with Severe Bloodstream Infections