The prevalence and characteristics of adults with latent tuberculous infection in the United States and the implications for healthcare in Texas

The Centers for Disease Control and Prevention reported 8,916 cases of tuberculosis in 2019. Reducing the number of cases of active tuberculosis requires identification of patients with latent tuberculous infections (LTBI). Optimal screening for LTBI requires information about the demographics and characteristics of people who are more likely to have had tuberculous infection. Information from the 2011–2012 National Health and Nutrition Examination Survey (NHANES) was used to determine the number and characteristics of adults from a representative sample of the United States who had LTBI. Latent tuberculous infection was identified either by a positive skin test or by a positive QuantiFERON blood test. Information about the number of patients with active tuberculosis in Texas was determined from reports from the Texas State Department of Health Services. The NHANES database for the years 2011-2012 included 5,684 adults. Participants with a positive QuantiFERON blood test were more likely in the age group 45-64, male, foreign born, and have less than a high school education. Participants with a positive skin test had similar characteristics. Participants who had both a positive skin test and positive QuantiFERON test were more likely to be in the age group 45-64, males, foreign born, and Hispanic. In addition, they had diabetes, self-reported fair/poor health, and an educational level less than high school. In the State of Texas tuberculosis occurred more frequently in individuals older than 75 who were male and were not US born Texas residents. Important clinical diagnoses included diabetes, alcohol abuse, correctional facility residence, non-injection drug use, positive HIV status, and homelessness. Information from the NHANES study and from the State Department of Health Services in Texas provides information needed to develop screening programs for latent tuberculosis and active tuberculosis.

Assessment of immediate and non-immediate hypersensitivity contrast reactions by skin tests and provocation tests: A review

Introduction: Allergic and nonallergic hypersensitivity reactions to iodinated contrast media (ICM) and gadolinium-based contrast media are classified as immediate or non-immediate hypersensitivity reactions (IHR and NIHR), respectively. Skin tests and provocation tests are recommended for the evaluation of hypersensitivity reactions to contrast agents; however provocations are not common in clinical practice. Methods: A MEDLINE search was conducted to investigate studies comprising both skin tests and provocation tests that evaluated hypersensitivity reactions to ICM. Results: Nineteen studies were identified that reported on skin tests, followed by provocations. In the case of IHR to ICM, 65/69 (94%) patients with a positive skin test for the culprit media tolerated a challenge with a skin-test-negative alternative ICM. In IHR to ICM with a negative skin test for the culprit media, provocations were positive in 3.2%–9.1% patients. In the case of a NIHR to ICM with a positive skin test, provocation with a skin-test-negative agent was tolerated in 75/105 (71%) of cases. In NIHR with a negative skin test for the culprit agent, re-exposure to the culprit or an alternative was positive in 0%–34.6% patients. Provocations with the same ICM in skin test positive patients with IHR or NIHR were positive for a majority of the patients, although such provocation tests were rarely performed. Data on hypersensitivity reactions, skin tests and provocations with gadolinium-based contrast media were limited; however, they exhibited a pattern similar to that observed in ICM. Conclusion: In both ICM and gadolinium-based contrast media, the risk of an immediate repeat reaction is low when skin tests are negative. In contrast, a provocation with a skin-test-positive contrast medium showed a high risk of an immediate repeat hypersensitivity reaction. Therefore, a thorough medical history is necessary, followed by skin tests. A provocation is recommended, for diagnostic work-up, when the diagnosis is uncertain.