Delayed TB Diagnosis
Thomas R. Navin MD
Chief, Surveillance, Epidemiology, and
Outbreak Investigations Branch
Division of Tuberculosis Elimination
CDC
Test of Baseline Knowledge

How many patients are evaluated for TB each year in
the United States?

Are the number of persons evaluated going down or
staying stable?

Are delays in TB diagnosis getting worse?

Are delays worse for racial/ethnic minorities?
Patients Evaluated for TB at CDC-funded
Public Health Laboratories, 2008-2009
2008
Patients evaluated for TB
2009 % change
103,708
97,568
-5.9%
Patients with cultures positive
for M. tuberculosis
4,972
4,217
-15.2%
Ratio of patients evaluated to
patients diagnosed with TB
21 : 1
23 : 1
Measuring TB Diagnostic Delay
Preliminary Results from TBESC Task Order 23:
National Study of Early Diagnosis of TB in the African-American
Community
Co-Principal Investigators:
Dolly Katz, Ph.D., CDC
Rachel Royce, Ph.D., M.P.H., RTI International
Charles Wallace, Ph.D., Texas Department of Health
4
Months from Symptom Onset
to Diagnosis
(N=346)
Race
African-American
White
p=0.04
5
Mean
(SD)
Median
4.4
19.7
(6.1)
(48.4)
2
4
Months from Symptom Onset to First
Medical Care: Patient Delay
(N=346)
Race
African-American
White
p=0.8
6
Mean
(SD)
Median
2.4
9.2
(5.2)
(29.5)
1
1
Months from First Medical Care
to Diagnosis: Provider Delay
(N=346)
Race
African-American
White
p=0.4
7
Mean
(SD)
Median
2.2
4.5
(3.5)
(4.5)
1
1
Summary of Findings from Task Order 23:
Study of Patient and Provider Delay

Snap shot in time (rather than trend over time)

Both patient and provider delay observed

Delay not worse for African Americans compared
with whites
Contribution of Provider Diagnostic Delay
to 27 TB Outbreaks Investigated by CDC*
Contributing factors
Number of Outbreaks where
item was considered a
contributing factor
Prolonged infectious
period
Provider-related
diagnostic delay
Patient-related delay
in access to care
* From: Mitruka et al., EID 2011;17(3):425
24
12
6
National TB Surveillance System:
Trends in culture-positive, smear-negative
pulmonary TB
Data from Recent TB Outbreak
Cases by sputum smear status
6
5
TB Cases
4
Smear-negative
Smear-positive
3
2
1
0
Mar Apr May Jun Jul Aug Sep Oct
Treatment Start Date
Culture-confirmed Pulmonary TB by
Sputum Smear Status, United States
2000-2009
5000
TB Cases
4000
3000
Smear positive
Smear negative
2000
Smear status unknown/not done
1000
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Proportion of Pulmonary TB Cases*
That Are Sputum Smear-Negative,
United States, 2000-2009
100%
80%
60%
40%
20%
0%
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
•Culture-positive TB cases
Proportion of Pulmonary TB Cases*
That Are Sputum Smear-Negative,
by Race/Ethnicity
United States, 2000-2009
100%
80%
60%
White
Black
Hispanic
40%
20%
0%
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
TB Case Count Date
* Culture-positive TB cases
Test of What You Have Learned

How many patients are evaluated for TB each year in
the United States?

Are the number of persons evaluated going down or
staying stable?

Are delays in TB diagnosis getting worse?

Are delays worse for racial/ethnic minorities?
Test of What You Have Learned

How many patients are evaluated for TB each year in
the United States?
 100,000 persons evaluated each year at public health labs alone
 Ratio of evaluated-to-diagnosed: 20+

Are the number of persons evaluated going down or
staying stable?
 Number is going down, but ratio of evaluated-to-diagnosed may
be going up
Test of What You Have Learned

Are delays in TB diagnosis getting worse?
 Data are not good, but no evidence of worsening

Are delays worse for racial/ethnic minorities?
 Data are not good, but no evidence of a difference
Getting Physicians to “Think TB” is asking
them to look for a needle in a haystack
Lung CA
TB (0.3%)
Community-acquired
pneumonia
Can Physicians be Educated to “Think TB”?
• As TB rates decline, general medical expertise
and education targeted at TB will decline
• Untargeted campaigns may not be successful
• “Think TB” campaigns may have impact in
targeted situations:
• In high-risk communities
• During outbreaks
Can Physicians be Educated to “Think TB”?
Challenges During TB Outbreaks
• Most media stories about TB “outbreaks”
describe contact investigations at schools
• Most contact investigations at schools do not
detect additional TB cases
• Health Departments often work hard to keep
information on large TB outbreaks out of media
Outbreak-associated TB cases can make up a significant
portion of TB cases in a community and can continue for years
Outbreak Associated TB Cases, 2002-2010
(N=109)
25
15
10
5
a
As of August 2010
20
10
*
20
09
20
08
20
07
20
06
20
05
20
04
20
03
0
20
02
No. of cases
20