Cedars-Sinai

Medical Staff Pulse Newsletter

Core Labs Changing Procalcitonin Assay March 10

The Core Laboratories within the Department of Pathology and Laboratory Medicine will be changing its procalcitonin (PCT) assay from a Roche to an Abbott immunoassay beginning Tuesday, March 10. PCT is used to diagnose and monitor sepsis, particularly early sepsis.

The reference cutoff for normal individuals will nominally change from < 0.09 ng/mL (Roche) to < 0.08 ng/mL (Abbott). Both manufacturer's immunoassays utilize the same antibodies so correlation of results is excellent.

However, the Abbott assay does not incorporate streptavidin-biotin binding in its methodology, whereas Roche does, so the Abbott assay is not subject to potential biotin interference from patients consuming dietary supplements.

Abbott also has extended clinical claims approved by the FDA, but these are already reflected in the existing comments we append to all PCT results (as shown below), which were derived from literature and were reviewed by our Antimicrobial Stewardship Committee.

If you have questions, contact Kimia Sobhani at kimiasobhani@cshs.org, or Anders Berg, PhD, at anders.berg@cshs.org.

Reference Range: Less than or equal to 0.08 ng/mL.

For suspected sepsis:

Initial Procalcitonin <0.5 ng/mL: antibiotics discouraged.

Repeat Procalcitonin <0.5 ng/mL or a decrease of >80% from peak: supports antibiotic discontinuation.

Repeat Procalcitonin <0.25 ng/mL: strongly supports antibiotic discontinuation.

For suspected pulmonary infections:

Initial Procalcitonin <0.25 ng/mL: antibiotics discouraged.

Repeat Procalcitonin <0.25 ng/mL or a decrease of >80% from peak: supports antibiotic discontinuation.

Procalcitonin <0.1 ng/mL or decrease of >90% from highest value: strongly supports antibiotic discontinuation.

An increase in Procalcitonin or prolonged elevated levels requires re-evaluation for source control, may represent inadequate treatment of infection, or may be due to conditions causing false positive results.

Sager R, Kutz A, Mueller B, et al. Procalcitonin-guided diagnosis and antibiotic stewardship revisited. BMC Medicine 2017: 15:15-25.”