Diagnosis of pulmonary tuberculosis

Diagnosis of Pulmonary Tuberculosis Mycobacteriology Sputum examination, the AFB smear Sputum culture Amplicor Mycobacterium tuberculosis test - DNA polymerase chain reaction amplification Image - Chest X-Ray, Chest CT Whole-blood interferon-gamma assay ELISA, eg, QuantiFERON assay [QFT-TB] - ELISPOT, eg, T SPOT-TB assay

Sputum examination Three specimens optimal Spot specimen on first visit; sputum container given to patient Early morning collection by patient on next day Spot specimen during second visit Sputum induction with nebulized, hypertonic (three to five percent) saline. Bronchoscopy.

Three sputum smears are optimal 10-13% 5-8% World Health Organization; 1998.

Fluorochrome stain of sputum

Quantitation scale for acid-fast bacillus smears according to stain used Am J Respir Crit Care Med Vol 161. pp 1376–1395, 2000

Sputum stained by Ziehl-Neelsen

Sputum smears 위음성 객담의 부적절한 채취 객담의 보관 잘못 (직사광, 자외선, 과한 열, 냉장 상태가 아닌 곳에서 1주 이상 보관) 적절한 객담 표본 채취 실패 도말 및 염색 잘못 검경 잘못 (검경 시간 부족, 소수 시야만 관찰) 검사자의 시력 및 정신적인 이유 기록 잘못 위양성 음식물 입자 섬유 (양모,면사,여과지,죽순) 화분 (소나무) 염료 결정, 오래된 염색 약 고초균 포자 슬라이드 긁힌 자국 염색 중 오염 토양이나 물의 비결핵 항산균 오염 기록 잘못 대한 결핵 및 호흡기 학회, 호흡기학, p841

Sputum Culture

Quantitation scale for mycobacterial growth on agar plates Am J Respir Crit Care Med Vol 161. pp 1376–1395, 2000

Sputum Culture Solid media Ogawa, Lowenstein-Jensen Middlebrook 7H10, 7H11 Eight weeks Liquid media BACTEC 460, MGIT Seven days Drug susceptibility testing

Tuberculosis direct amplified tests Thorax 1996; 51:320.

Tuberculin skin test False negatives Technical factors Application Reading Improper storage of PPD Biological factors Poor nutrition Infection Immunosuppressive drugs Malignancy Age Stress False positives Infection with nontuberculous mycobacteria BCG vaccination

Quanti-FERON-TB Gold It can be used in all circumstances in which the TST is used, including Ongoing potential close contact with cases of active TB HIV infection Evaluation of recent immigrants who have had BCG vaccination Member of a medically underserved, low-income population (eg, homeless, injection drug users) Presence of an incidentally discovered fibrotic lung lesion Residence in a long term care facility Others undergoing serial evaluation for M. tuberculosis infection CDC, MMWR, December 16, 2005 / Vol. 54 / No. RR-15, pp. 49-54

Quanti-FERON-TB Gold Interferon Gamma Release

Quanti-FERON-TB Gold In vitro test using whole blood specimen , Interferon γ release assay TB infection, whether latent or active The recognition process -> interferon-γ, a specific cytokine for cell mediated immune response Synthetic peptide antigens (ESAT-6, CFP-10) -> simulate mycobacterial proteins to generate the immune response

Quanti-FERON-TB Gold Assay

Results and Interpretation of Quanti-FERON-TB Gold CDC, MMWR, December 16, 2005 / Vol. 54 / No. RR-15, pp. 49-54

Specificity Estimates of Quanti-FERON-TB Gold 216 healthy individuals, no identified risk for TB infection, all BCG (+) Specificity = 98% (213/216 = QFT- Gold negative) AJRCCM 2004;170:59-64 532 with no identified risk for TB infection among Navy recruits Specificity = 99.8% (531/532 = QFT- Gold negative) CDC; publication in preparation 2005 99 healthy individuals with no identified risk for TB infection, all BCG (+) Specificity = 96% (95/99 = QFT negative) JAMA 2005;293:2756-2761

Sensitivity Estimates of Quanti-FERON-TB Gold 118 culture confirmed TB disease, 85% untreated, 15% treated < 7 days 65.8% had positive TST (5mm); Sensitivity 105/118 = 89% for QFT Mori, et al. AJRCCM 2004;170:59-64 48 culture confirmed TB disease, 71% untreated Sensitivity 41/48 = 85.4% Ravn, et al. Clin Diag Lab Immunol 2005;12:491-496 54 culture confirmed TB disease Sensitivity 44/54 = 81.5%; TST = 77.8% Kang, et al. JAMA 2005;293:2756-2761

Characteristic of the Quanti-FERON-TB Gold Am J Respir Crit Care Med Vol 174. pp 736–742, 2006

Quanti-FERON-TB Gold Species Specificity of ESAT-6 and CFP-10