Procalcitonin in sepsis and bacterial infections

Use of full blood count parameters and haematology cell ratios in screening for sepsis in South Africa

Background

Sepsis is characterised by multi-organ failure due to an uncontrolled immune response to infection. Sepsis prevalence is increased in developing countries and requires prompt diagnosis and treatment. Reports, although controversial, suggest that full blood count parameters and cell ratios could assist in the early screening for sepsis.

Objective

The study evaluated the use of haematological cell ratios in screening for sepsis in a South African population.

Methods

The study retrospectively analysed the complete blood counts, blood cultures (BC) and biochemical test results of 125 adult patients who presented between January 2021 and July 2021 at a hospital in Cape Town. An ISO15189-accredited laboratory performed all of the tests. We compared and correlated the automated differential counts, neutrophil, monocyte and platelet-to-lymphocyte ratios with procalcitonin levels. A p-value of < 0.05 was considered significant.

Results

Sixty-two sepsis patients (procalcitonin > 2 ng/L and positive BC) were identified and compared to 63 non-sepsis controls. All cell ratios were significantly elevated in sepsis patients (p < 0.001). However, the two groups had no significant difference in absolute monocyte counts (p = 0.377). In addition, no correlation was detected between any cell ratios and procalcitonin.

Conclusion

In combination with complete blood count parameters, haematology cell ratios can be used for early sepsis detection. The full blood count is widely available, inexpensive, and routinely requested by emergency care clinicians. Although procalcitonin and BC remain the gold standard, the calculation of cell ratios could provide a simple screening tool for the early detection of sepsis.

What this study adds

This study adds evidence to the proposal that calculating haematological cell ratios assists in the early screening of sepsis in a South African setting.

The role of procalcitonin and presepsin in the septic febrile neutropenia in acute leukemia patients

BACKGROUND

The source of bacterial infection in neutropenic acute leukemia patients is detected in about 20-30% of cases. Bacterial cultures may require a long incubation period and risk false-positive and false- negative results. Therefore, biomarkers distinguishing septic febrile neutropenia from other etiologies in acute leukemia patients play the important role in patient assessment and treatment planning. This study aims to determine the role of procalcitonin (PCT) and presepsin (PSPN) in infectious complication in comparison to C-reactive protein (CRP) on the first and third day at the onset of febrile neutropenia in patients with acute leukemia.

METHODS

Between June 2018 and February 2019, 60 acute leukemia patients with febrile neutropenia receiving chemotherapy. The 41 acute myeloid leukemia patients and 19 acute lymphoblastic leukemia patients were recruited in this study. Their ages ranged from 14 to 65 years. PCT and PSPN were measured and were compared to CRP at the onset of febrile neutropenia and after 48 hours. 20 patients had a fever of unknown origin (FUO) and 40 patients had a bacterial infection.

FINDINGS

Our results showed that the values of these markers were higher in patients with infection than patients without. The area under the curve (AUC) of PCT were 0.931 and 0.813 on day one and three respectively, which was the best in determination of infection. The cut-off values of PCT were 1.27 and 1.23 ng/mL and the cut off values of PSPN were 1.75 and 2.9 μg/L in the successive days, their clinical sensitivities were high. PCT and PSPN were capable of distinguishing the cause of febrile neutropenia from the onset of infection and predicting its complications (p<0.05). The PSPN level couldn't differentiate gram-positive or gram-negative bacterial infection. Significant differences were found between the mean values of the PSPN during the successive days in all patients and patients with bacteremia. This study illustrated a weak positive correlation between PCT and Sequential Organ Failure Assessment (SOFA) score, the negligible correlation between CRP and SOFA score and no significant correlation between PSPN and SOFA score.

INTERPRETATION

PCT is an accurate biomarker in identifying infection in acute leukemia patients, its concentration is associated with the severity of bacterial sepsis. PSPN is superior to PCT for follow-up of patients.

Comparison between presepsin and procalcitonin in early diagnosis of neonatal sepsis

Background: Neonatal sepsis remains worldwide one of the leading causes of morbidity and mortality in both term and preterm infants. Lower mortality rates are related to timely diagnostic evaluation and prompt initiation of empiric antibiotic therapy. Blood culture, as gold standard examination for sepsis, has several limitations for early diagnosis, so that sepsis biomarkers could play an important role in this regard. This study was aimed to compare the value of the two biomarkers presepsin and procalcitonin in early diagnosis of neonatal sepsis. Methods: This was a prospective cross-sectional study performed in Saiful Anwar General Hospital Malang, Indonesia, in 51 neonates that fulfill the criteria of systemic inflammatory response syndrome (SIRS) with blood culture as diagnostic gold standard for sepsis. Results: At reviewer operating characteristic (ROC) curve analyses, using a presepsin cutoff of 706.5 pg/mL, the obtained area under the curve (AUCs) were sensitivity = 85.7%, specificity = 68.8%, positive predictive value = 85.7%, negative predictive value = 68.8%, positive likelihood ratio = 2.75, negative likelihood ratio = 0.21, and accuracy = 80.4%. On the other hand, with a procalcitonin cutoff value of 161.33 pg/mL the obtained AUCs showed: sensitivity = 68.6%, specificity = 62.5%, positive predictive value = 80%, negative predictive value = 47.6%, positive likelihood ratio = 1.83, the odds ratio negative = 0.5, and accuracy = 66.7%. Conclusions: In early diagnosis of neonatal sepsis, compared with procalcitonin, presepsin seems to provide better early diagnostic value with consequent possible faster therapeutical decision making and possible positive impact on outcome of neonates.