8
Diagnosis of Pulmonary Tuberculosis
Three specimens optimal
Spot specimen on first visit; sputum container given to patient Early morning collection by patient on next day
Actual cases
15
Role of Chest X-ray
No chest X-ray pattern is absolutely typical of TB 10-15% of culture-positive TB patients not diagnosed by X-ray 40% of patients diagnosed as having TB on the basis of x-ray alone do not have active TB
X-ray is unreliable for diagnosing and monitoring treatment of tuberculosis
结核病的有效诊断，治疗和控制-英文
South-East Asia accounts for nearly 40% of all tuberculosis cases
EUR AMR EMR 6% 5% 8%
AFR 18%
SEAR 38%
WPR 25%
2
Tuberculosis
A Global Emergency
1+
1-10 per oil immersion field
2+
> 10 per oil immersion field
3+
11
Diagnosis of Pulmonary TB
Cough 3 weeks
If 1 positive, X-ray and evaluation
AFB XDiagnosis of pulmonary tuberculosis
Patients with TB feel ill and seek care promptly Active case finding is unnecessary and unproductive Microscopy is appropriate technology, indicating infectiousness, risk of death, and priority for treatment X-ray is non-specific for TB diagnosis Serological and amplification technologies (PCR, etc.) currently of no proven value in TB control
TB kills 5,000 people a day – 2-3 million each year One third of the world’s population is infected with TB TB kills more young women than any other disease More than 100,000 children will die needlessly from TB this year Hundreds of thousands of children will become TB orphans this year
98% 100
80 60 40 20
0
AFB Microscopy
Inter-observer agreement
70%
X-ray
13
Microscopy is a more specific test than X-ray for TB diagnosis
100
98%
80
Specificity
60
If 2/3 positive: Anti-TB Rx
Broad-spectrum antibiotic 10-14 days
If symptoms persist, repeat AFB smears, X-ray
If consistent with TB
Anti-TB Treatment
12
Microscopy is more objective and reliable than X-ray
50%
40
20
0
AFB Microscopy
X-ray
14
X-ray-based evaluation causes over-diagnosis of TB
100 80 60 40 20 0
Diagnosed by Xray alone
NTI, Ind J Tuberc, 1974
Overdiagnosis
Spot specimen during second visit
9
Three sputum smears
are optimal
100%
81%
93%
100%
50%
Cumulative Positivity
0%
First
Second
Third
10
Reporting on AFB Microscopy
Number of bacilli seen None per 100 oil immersion fields
Result reported Negative
1-9 per 100 oil immersion fields 10-99 per 100 oil immersion fields
Scanty, report exact number
5
TB and AIDS
Lifetime Risk
70%
of TB
60%
50%
40%
30%
20% 10%
10%
0%
PPD+/HIV-negative
60%
PPD+/HIV+
6
TB Control: The 5 components of DOTS
Political commitment Diagnosis by microscopy Adequate supply of SCC drugs Directly observed treatment Accountability