A pregnancy-specific reference interval for procalcitonin.

BACKGROUND AND AIMS: Sepsis is a leading cause of maternal death, and developing diagnostic tests for infection is increasingly important to reduce maternal mortality. The existing inflammatory markers, like C-reactive protein, are not specific for infection, which introduces diagnostic uncertainty. Procalcitonin (PCT) is used to accurately diagnose bacterial sepsis and differentiate it from other conditions, which is now particularly important given the vulnerability to COVID-19 in pregnancy. There are few studies of PCT in pregnancy as the reference interval for pregnant women is unknown. This study aimed to define the pregnancy-specific reference interval for PCT. MATERIALS AND METHODS: Cross-sectional study of 323 healthy pregnant women, with longitudinal sampling in each trimester. RESULTS: The upper reference limit for PCT was 0.05 ng/mL and did not vary materially between any observed group of gestational age, body mass index, maternal age, mean arterial blood pressure or fetal sex. CONCLUSION: Our study has shown that levels of PCT are similar in pregnant and non-pregnant populations despite the physiological changes of normal pregnancy. Therefore, pregnancy should not preclude the use of PCT in pregnant women with suspected sepsis, or for guiding antibiotic therapy in women with a diagnosed bacterial infection at any stage of pregnancy.

Accuracy of C-reactive protein, procalcitonin, serum amyloid A and neopterin for low-dose CT-scan confirmed pneumonia in elderly patients: A prospective cohort study.

OBJECTIVE: The diagnosis of pneumonia based on semiology and chest X-rays is frequently inaccurate, particularly in elderly patients. Older (C-reactive protein (CRP); procalcitonin (PCT)) or newer (Serum amyloid A (SAA); neopterin (NP)) biomarkers may increase the accuracy of pneumonia diagnosis, but data are scarce and conflicting. We assessed the accuracy of CRP, PCT, SAA, NP and the ratios CRP/NP and SAA/NP in a prospective observational cohort of elderly patients with suspected pneumonia. METHODS: We included consecutive patients more than 65 years old, with at least one respiratory symptom and one symptom or laboratory finding suggestive of infection, and a working diagnosis of pneumonia. Low-dose CT scan and comprehensive microbiological testing were done in all patients. The index tests, CRP, PCT, SAA and NP, were obtained within 24 hours. The reference diagnosis was assessed a posteriori by a panel of experts considering all available data, including patients' outcome. We used area under the curve (AUROC) and Youden index to assess the accuracy and obtain optimal cut-off of the index tests. RESULTS: 200 patients (median age 84 years) were included; 133 (67%) had pneumonia. AUROCs for the diagnosis of pneumonia was 0.64 (95% CI: 0.56-0.72) for CRP; 0.59 (95% CI: 0.51-0.68) for PCT; 0.60 (95% CI: 0.52-0.69) for SAA; 0.41 (95% CI: 0.32-0.49) for NP; 0.63 (95% CI: 0.55-0.71) for CRP/NP; and 0.61 (95% CI: 0.53-0.70) for SAA/NP. No cut-off resulted in satisfactory sensitivity or specificity. CONCLUSIONS: Accuracy of traditional (CRP, PCT) and newly proposed biomarkers (SAA, NP) and ratios of CRP/NP and SAA/NP was too low to help diagnosing pneumonia in the elderly. CRP had the highest AUROC. CLINICAL TRIAL REGISTRATION: NCT02467092.

Procalcitonin as a Biomarker of Unresponsiveness to Intravenous Immunoglobulin for Kawasaki Disease.

OBJECTIVE: To investigate the usefulness of procalcitonin (PCT) as predictive factors of intravenous immunoglobulin (IVIG)-resistant Kawasaki disease patients. METHODS: We retrospectively analyzed the laboratory data from 215 children with Kawasaki disease treated with IVIG from 2014 to 2019. We analyzed the clinical and laboratory parameters just before the IVIG including serum levels of PCT with respect to the IVIG response. RESULTS: Eventually, 127 patients were analyzed. The median age was 2.4 years. IVIG was effective in 108 children (responders) and was ineffective in 19 (non-responders). Serum PCT concentration was higher in non-responders than those of responders (P < 0.001). Multivariate logistic regression analyses indicated that higher PCT concentration (odds ratio 1.34, 95% confidence interval 1.10-1.64) were associated with IVIG resistance. Analyses of the receiver operating characteristic curve showed that the cutoff value of PCT 2.18 ng/mL had 46.4% of sensitivity and 93.9% of specificity. Receiver operating characteristic analysis yielded an area under the curve of 0.82 (0.72-0.92) to predict IVIG resistance. CONCLUSIONS: Serum PCT value can be an excellent biomarker for predicting unresponsiveness to IVIG with a good discriminatory ability as well as the existing prediction scores.

Reduced utility of early procalcitonin and blood culture determination in patients with febrile urinary tract infections in the emergency department.

To investigate the prognostic role of procalcitonin (PCT) assessment and blood culture (BC) acquisition in the emergency department (ED) in patients with urinary tract infection (UTI) or urosepsis. We enrolled patients admitted for UTI to our ED over a 10-year period. Mortality and in hospital length of stay (LOS) were compared between patients with UTI or urosepsis who had sampling for PCT levels and BC taken in the ED (ePCT group-eBC group) and those who had not (no-ePCT group-no-eBC group). 1029 patients were analyzed, 52.7% of which were female. Median age was 77 [65-83]; 139 patients (13.5%) had complicated UTI. Median LOS was 10 [7-17] days. In the ePCT group, LOS was 10 [7-16] days, vs. 10 [7-17] (p = 0.428) in the no-ePCT group. In the eBC group, LOS was 10 [6-16] days vs. 10 [7-17] days (p = 0.369) in the no-eBC group. The overall mortality rate was 6.6%. The mortality rate was not affected by early PCT determination (6% in the ePCT group vs. 6.9% in the no-ePCT group, p = 0.584). Similarly, the mortality rate was not different in the eBC group as compared to the no-eBC group (5.4% vs. 6.9%, p = 0.415). Performance of ePCT or eBC testing made no significant difference in terms of improvement of mortality rates in septic patients (11.4% vs. 7.2%; p = 0.397 and 8.8% vs. 9.8%; p = 0.845, respectively). The prognostic relevance of early evaluation of PCT and BC in the ED of patients with febrile UTI appears limited. In complicated UTI patients, PCT and BC testing may be more appropriate in the context of improving antibiotic stewardship, or as an integral component of PCT-guided standardized protocols.