Investigation of Underdiagnosis
Review of 2008 and 2009 laboratory data in both states showed that the total number of patients who had specimens tested for mycobacteria increased in the public health laboratories (i.e., 4.7% in Georgia and 11.6% in Pennsylvania), but the proportion of patients with specimens that tested positive for M. tuberculosis complex decreased 19.8% in the Georgia State Public Health Laboratory and 28.8% in Pennsylvania public health laboratories (Table). In the 10 private laboratories that provided these data in response to the Georgia survey, a parallel decline was noted. Among 131 private laboratories responding to the Pennsylvania survey, similar numbers of specimens were received for M. tuberculosis complex testing annually during 2007–2009, but the proportion that tested positive for M. tuberculosis complex decreased 36% from 2008 to 2009 (Figure 2). In neither state were changes noted in the types of specimens processed or in the methods or procedures (at public health labs) for laboratory diagnosis of TB.
Figure 2.
Number of specimens tested* and percentage of positive results for Mycobacterium tuberculosis complex from 131 private laboratories — Pennsylvania, 2007–2009
* The presence of Mycobacterium tuberculosis complex was determined using either culture with identification or nucleic acid amplification testing.
Analysis of the southeastern Pennsylvania hospital discharge dataset showed that the total number of inpatient hospitalizations was stable, with 707,601; 699,893; and 696,846 discharges in 2007, 2008, and 2009, respectively. Time-trend analysis revealed that the percentage of all hospitalizations with either pulmonary or extrapulmonary TB as a primary or secondary diagnosis was approximately 0.04% each year; further subset analyses by TB-related ICD-9 codes revealed no other TB diagnosis-related changes during this period.
Morbidity and Mortality Weekly Report. 2011;60(11):338-342. © 2011 Centers for Disease Control and Prevention (CDC)
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