1649 - Characterizing Factors Associated with Pediatric Latent Tuberculosis Infection in an Urban Health System to Improve Screening Practices

Background: The epidemiology and risk factors informing current American Academy of Pediatrics (AAP) guidelines on screening for pediatric latent tuberculosis infection (LTBI) have evolved over the past decade. To improve pediatric LTBI screening efficiency, we sought to reevaluate characteristics associated with positive QuantiFERON-TB Gold Plus (QFT-Plus) at Denver Health (DH), an urban health system that includes a network of primary care clinics, a refugee clinic and a tuberculosis clinic.

Methods: We retrospectively analyzed all QFT-Plus tests performed on children aged 2-18 years from 1/2019 to 9/2019. To obtain additional variables we conducted chart review on all positive and indeterminate results, and a random 10% sample of negatives. Characteristics (age range, sex, region of birth, clinic setting, primary language) of patients with positive and negative QFT-Plus were compared using Chi² or Fisher’s exact tests (Table 1).  Using the 10% negative controls, we calculated odds ratios for each variable and included important or significant variables in a multivariable logistic regression model.

Results: Of 1063 QFT-Plus tests performed, 29 (2.7%) were positive. 76% of all positive tests and 83% of positive tests in primary care clinics occurred in patients age ≥10.  51.7% of all positive patients were born in the US. Among factors analyzed by logistic regression including birth region, reason for screening, sex, age, ordering location, insurance status, and language, only Spanish language (OR 5.0, CI 1.6-15.8) and non-English, non-Spanish language (OR 6.4, CI 1.4-28.5) were significant risk factors for positive testing.Characteristics of Denver Health Patients with Positive and Negative QFT-Plus, January-September 2019.


Conclusion: Language was the only predictor of LTBI in this study, and may be a proxy for high risk travel and family exposure. Region of birth was not predictive, as half of positive tests occurred in US-born children. The majority of positive tests occurred in older children, suggesting they should be prioritized in screening programs, though occasional detection among younger children reinforces the importance of LTBI detection in ages where risk of progression to active TB is higher. Further studies are needed to better elucidate the details behind positive testing, including more detailed characterization of travel and potential family exposures.