BACKGROUND: As stated in ‘The Action Strategy for Tuberculosis-Free Korea,’ last March, high-throughput, large-scale analytical instruments for interferon gamma release assays (IGRA) are demanded by many clinical laboratories using the QuantiFERON-TB Gold In-Tube assay (Cellestis/Qiagen, Australia). Agility (Dynex Technologies, USA) is an automated high-throughput enzyme linked immunosorbent assay analyser. The present study aimed to evaluate its accuracy and speed. METHODS: Pooled plasma was prepared using samples obtained after IGRA testing. Analyses of precision, linearity, cut-off evaluation, and comparison with conventional methods were performed for multiple Agility instruments according to the Clinical and Laboratory Standards Institute EP5-A3, EP6-A, EP9-A3 and EP12-A2 guidelines. The turnaround time and throughput were also analysed. RESULTS: The coefficient of variation range was 2.48%–4.0%, 7.01%–11.17%, and 9.69%–14.84% for the repeatability, between-run precision, and between-day precision analyses, respectively. The linearity ranged from 0 to 10.541. Comparison analysis presented a high concordance of Agility with the conventional instrument, DS2 (Dynex Technologies), and manual method for IGRA. The cut-off value of 0.35 IU/mL was well compatible with the C50. It was identified that the C50±20% contained the C5–C95 interval. The average turnaround time was 3.84 hours, from the submission of pre-treated samples to the reporting of results. The throughput was determined to be 290 tests during a routine working time of 8 hours. CONCLUSIONS: Agility showed high precision, linearity, concordance, and had a 2.5 times faster throughput than with the conventional and manual method. It could be useful for large-scale IGRA testing in latent tuberculosis infection screening project. Samples within C50±20% are suspected to show relatively low reporducible results of high inversion between postivie and negative.
Enzyme-Linked Immunosorbent Assay ; Interferon-gamma Release Tests ; Interferons ; Latent Tuberculosis ; Mass Screening ; Methods ; Plasma

BACKGROUNDTuberculosis (TB) remains a major global public health challenge. Articular TB is an important form of extrapulmonary tuberculosis, and its diagnosis is difficult because of the low sensitivity of traditional methods. The aim of this study was to analyze the diagnostic value of T-SPOT.TB on synovial fluid for the diagnosis of articular TB.

METHODSPatients with suspected articular TB were enrolled consecutively between August 2011 and December 2015. T-SPOT.TB was performed on both synovial fluid mononuclear cells (SFMCs) and peripheral blood mononuclear cells (PBMCs). The final diagnosis of articular TB was independent of the T-SPOT.TB result. The diagnostic sensitivity, specificity, predictive value, and likelihood ratio of T-SPOT.TB on SFMCs and PBMCs were analyzed.

RESULTSTwenty patients with suspected articular TB were enrolled. Six were diagnosed with articular TB, and 14 patients were diagnosed with other diseases. Sensitivity and specificity were 83% and 86% for T-SPOT.TB on SFMCs, and 67% and 69% for T-SPOT.TB on PBMCs, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of T-SPOT.TB on SFMCs were 71% and 92%, respectively. The PPV and NPV were 50% and 82% for T-SPOT.TB on PBMCs.

CONCLUSIONSensitivity, specificity, and NPV of T-SPOT.TB on SFMCs appeared higher than that on PBMCs, indicating that T-SPOT.TB on SFMCs might be a rapid and accurate diagnostic test for articular TB.

Adult ; Female ; Humans ; Interferon-gamma Release Tests ; methods ; Male ; Middle Aged ; Pilot Projects ; Synovial Fluid ; chemistry ; Tuberculosis ; diagnosis ; Young Adult

PURPOSE: We investigated the value of an interferon-gamma release assay (IGRA) for the diagnosis of active pulmonary tuberculosis (PTB) among sputum smear negative PTB suspects in an environment with intermediate burden of PTB and high Bacillus Calmette-Guerin (BCG) vaccination rate. MATERIALS AND METHODS: We retrospectively reviewed IGRA, medical records, chest PA and CT scan of PTB suspects seen at Gangnam Severance Hospital, Seoul, Korea from Oct. 2007 to Apr. 2013. "Active PTB" was diagnosed when 1) M. tuberculosis culture positive, 2) confirmation by pathologic examination; or 3) clinical findings compatible with TB. RESULTS: Of 224 sputum smear negative PTB suspects, 94 were confirmed as having active PTB. There were no statistically significant differences in the diagnostic yield of IGRA between immunocompromised and immunocompetent sputum smear negative PTB suspects. IGRA did show superior sensitivity [81.9%, 95% confidence interval (CI); 74.13-89.70%] in the diagnosis of sputum smear negative PTB when compared with chest high-resolution computed tomography (HRCT), tuberculin skin test (TST), and chest X-ray (p<0.001). Also, IGRA showed highest negative predictive value (82.7%, 95% CI; 75.16-90.15%) when compared with HRCT, TST and chest X-ray (p=0.023). However, combining the results of IGRA with those of HRCT, TST, or both did not increase any diagnostic parameters. CONCLUSION: Failure to increase diagnostic yields by combination with other diagnostic modalities suggests that additional enforcement with IGRA may be insufficient to exclude other diagnoses in sputum smear negative PTB suspects and to screen active PTB in an environment with intermediate TB prevalence and a high BCG vaccination rate.
Adult ; Aged ; Female ; Humans ; Interferon-gamma Release Tests/*methods ; Male ; Middle Aged ; Retrospective Studies ; Sputum/*microbiology ; Tuberculosis, Pulmonary/blood/*diagnosis/metabolism

OBJECTIVE: To evaluate the value of T-SPOT.TB in the diagnosis of tuberculous peritonitis (TBP). METHODS: A total of 50 patients with clinically suspected TBP admitted from August 2011 to July 2012 from the Third Xiangya Hospital were enrolled in this prospective cohort study. Peripheral blood T-SPOT.TB, purified protein derivatives of tuberculin (PPD) skin test, serum tuberculosis antibody (TB-Ab) and ascitic adenosine deaminase (ADA) were measured in the 50 patients and we compared the diagnostic value of the 4 methods. RESULTS: According to the standard of diagnosis of TBP and grouping, 24 patients were diagnosed with TBP, 17 non-TBP and 9 undiagnosed in the end. The sensitivity of T-SPOT.TB for the diagnosis of TBP was 91.7% (22/24), with statistical significance when compared with PPD skin test 37.5% (9/24), serum TB-Ab 16.7% (4/24), and ascitic ADA 36.4% (8/22) (P<0.01). The specificity of T-SPOT.TB for the identification of non-TBP was 76.5% (13/17), without statistical significance when compared with PPD skin test 70.0% (7/10), serum TB-Ab 78.6% (11/14), and ascitic ADA 100% (14/14) (P>0.05). The positive prediction value of T-SPOT.TB for the diagnosis of TBP was 84.6% (22/26), without statistical significance when compared with PPD skin test 75.0% (9/12), serum TB-Ab 57.1% (4/7), and ascitic ADA 100%(8/8) (P>0.05). The negative prediction value of T-SPOT.TB for the identification of non-TBP was 86.7% (13/15), with statistical significance when compared with PPD skin test 31.8% (7/22), serum TB-Ab 35.5% (11/31), and ascitic ADA 50.0% (14/28) (P<0.05). CONCLUSION Peripheral blood T-SPOT.TB for the diagnosis of TBP is highly sensitive, which is better than PPD skin test, serum TB-Ab, and ascitic ADA. T-SPOT.TB has an important reference for diagnosing suspected TBP quickly and accurately.
Adolescent ; Adult ; Aged ; Child ; Enzyme-Linked Immunosorbent Assay ; methods ; Female ; Humans ; Interferon-gamma Release Tests ; methods ; Leukocytes, Mononuclear ; immunology ; Male ; Middle Aged ; Peritonitis, Tuberculous ; diagnosis ; Sensitivity and Specificity ; T-Lymphocytes ; immunology ; Young Adult

PURPOSE: To evaluate the usefulness of the interferon-gamma release assay (IGRA) for diagnosing tuberculosis (TB)-related uveitis (TRU). METHODS: Records from 181 patients with ocular signs and symptoms suggestive of TRU and intraocular inflammation of unknown etiology were reviewed. All subjects underwent clinical and laboratory testing, including IGRA, to rule out presence of underlying disease. A diagnosis of presumed TRU was made based on an internist's TB diagnosis and a patient's response to anti-TB therapy. Sensitivity, specificity, and positive predictive values of IGRA for TRU diagnosis were calculated. Clinical characteristics were compared between patients with positive and negative IGRA results. RESULTS: The sensitivity and specificity of IGRA for TRU were 100% and 72.0%, respectively. Mean age, percentage of patients with retinal vasculitis, and the anatomic type of uveitis were significantly different between patients with positive and negative IGRA results (all p < or = 0.001). Positive IGRA rates and false-positive rates were significantly different between age and anatomic type groups (both p = 0.001). The positive predictive value of the IGRA among patients with intraocular inflammation was high (70%) when all of younger age (< or =40 years), posterior uveitis, and retinal vasculitis were present. CONCLUSIONS: The IGRA is useful for diagnosing TRU in the Korean population, especially when it is used as a screening test. Clinical characteristics, including younger age (< or =40 years), posterior uveitis, and retinal vasculitis in IGRA-positive patients, increase the likelihood of the patient having TRU.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Female ; Humans ; Incidence ; Interferon-gamma/*analysis ; Interferon-gamma Release Tests/*methods ; Male ; Middle Aged ; Predictive Value of Tests ; Reproducibility of Results ; Republic of Korea/epidemiology ; Retrospective Studies ; Tuberculosis, Ocular/*diagnosis/epidemiology/microbiology ; Uveitis/*diagnosis/epidemiology/microbiology ; Young Adult