SHM Converge Scientific Abstract ePoster Gallery-False Negative Procalcitonin in a Patient With Staphylococus Aureus Bacteremia

Pdf Summary

This case report highlights a false-negative procalcitonin (PCT) result in a patient with true MRSA bacteremia. A 55-year-old woman presented with weakness, fever, and chills. Initial labs showed leukocytosis and elevated CRP, but PCT was very low (0.05 ng/mL) and lactate was normal. Because no clear infection source was identified and PCT was negative, antibiotics were initially withheld. However, blood cultures later grew MRSA on two occasions, and repeat PCT remained negative. Imaging and transesophageal echocardiography did not reveal a source. She was then treated with IV vancomycin and improved.<br /><br />The discussion reviews PCT as a biomarker commonly used to support decisions about starting or withholding antibiotics. PCT is generally helpful because of its high negative predictive value for bacteremia, especially at lower cutoff values. However, studies suggest PCT is more sensitive for gram-negative than gram-positive infections, and false negatives can occur. Staphylococcus aureus is a notable organism in these missed cases.<br /><br />The key message is that although a low PCT can help rule out bacteremia in many patients, it should not be used alone to exclude serious infection. Clinicians and antimicrobial stewardship programs should remain cautious, particularly when the clinical picture suggests infection despite a negative PCT, since false-negative results may occur in Staphylococcus aureus bacteremia.

Asset Subtitle

Sharath Kommu

Meta Tag

Author List Shalini Arepally, Sharath Kommu, Vidyasagar Reddy Cirra

Category Clinical Vignettes

Concept Procalcitonin

Concept Bacterial Infection

Concept Bacteremia

Concept Staphylococcus aureus

Concept Antimicrobial Stewardship

Distinguished Non-Finalist

Presenter Organization Marshfield Clinic Health System

Presenting Author Sharath Kommu

Track Adult

Keywords

procalcitonin

false-negative

MRSA bacteremia

Staphylococcus aureus

blood cultures

antibiotic stewardship

vancomycin

bacteremia

biomarker

infectious disease

Procalcitonin

Bacterial Infection

Bacteremia

Staphylococcus aureus

Antimicrobial Stewardship