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Published on: August 7, 2017
Procalcitonin levels in febrile infants after recent immunization
Andrew Dauber1, Scott Weiss, Vincenzo Maniaci
1Divisions of Endocrinology, Children's Hospital Boston, Boston, Massachusetts 02115, USA. andrew.dauber@childrens.harvard.edu
Insights
In febrile infants, recent immunizations can increase procalcitonin levels. However, procalcitonin remains a reliable marker for serious bacterial infections, even after vaccination.
Area of Science:
- Pediatric Emergency Medicine
- Infectious Disease Diagnostics
- Biomarker Research
Background:
- Procalcitonin is a key biomarker for serious bacterial infections in febrile infants.
- The impact of immunizations on procalcitonin levels in infants was previously unstudied.
Purpose of the Study:
- To investigate the effect of recent immunizations on procalcitonin levels in febrile infants.
- To determine if procalcitonin can still accurately diagnose serious bacterial infections post-immunization.
Main Methods:
- A prospective observational cohort study was conducted in a pediatric emergency department.
- Febrile infants (<=90 days) were categorized into three groups: serious bacterial infection, recent immunization, and no recent immunization.
- Procalcitonin levels were measured using a quantitative immunometric assay.
Main Results:
- Procalcitonin levels were elevated in infants with serious bacterial infection compared to both immunized and non-immunized groups.
- Infants who recently received immunizations showed higher procalcitonin levels than those without recent immunizations.
- A procalcitonin cut-off of 0.12 ng/mL demonstrated 96% sensitivity and 96% negative predictive value for serious bacterial infection.
Conclusions:
- Recent immunizations increase procalcitonin levels in febrile infants.
- Procalcitonin effectively distinguishes serious bacterial infections from other causes of fever, even in recently immunized infants.
Background:
Procalcitonin has been identified as a useful blood marker of serious bacterial infection in febrile infants. Many infants present with a febrile reaction after receiving immunizations. The effects of immunization on procalcitonin have not been investigated.
Methods:
We performed a prospective observational cohort study at a large, urban pediatric emergency department. Infants
Results:
Over 13 months, procalcitonin was measured for 271 infants. There were 44 (16%) patients with serious bacterial infection, 35 in the recent-immunization group, and 192 in the no-recent-immunization group. The median procalcitonin level for serious bacterial infection was 0.53 ng/mL, for recent immunization was 0.29 ng/mL, and for no recent immunizations was 0.17 ng/mL. Procalcitonin values were elevated for patients with serious bacterial infection compared with patients both with and without recent immunizations. Compared with patients who had no recent immunizations, procalcitonin levels were elevated in patients with recent immunization. Using a cut point of 0.12 ng/mL, the sensitivity of procalcitonin for serious bacterial infection was 96%, specificity was 23%, and negative predictive value was 96%. Two patients with recent immunization who had serious bacterial infection were identified with this cut point.
Conclusions:
Among febrile infants with recent immunization, procalcitonin levels are increased compared with patients with fever and no identified bacterial infection. Despite this increase, procalcitonin can still reliably discriminate infants with serious bacterial infection.
