Procalcitonin assay variation in an Australasian external quality assurance program

Area of Science:

• Clinical Chemistry
• Infectious Diseases
• Laboratory Medicine

Background:

• Sepsis causes ~20% of global deaths, making early diagnosis crucial.
• Procalcitonin (PCT) is FDA-approved to guide antibiotic use in suspected sepsis.
• Antibiotic stewardship is vital due to rising antibiotic resistance.

Purpose of the Study:

• To analyze variations in procalcitonin (PCT) assay performance using external quality assurance data.
• To investigate assay performance differences across manufacturers and over time (2019-2021).

Main Methods:

• Analysis of Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) PCT program results from 2019-2021.
• Statistical analysis including two-way ANOVA and Student's t-test to assess assay variation.
• Evaluation of both quantitative and semi-quantitative PCT methods.

Main Results:

• Significant variation in PCT assay performance was found among different manufacturers at all tested concentrations.
• Bimodal reporting was observed, with specific methods yielding higher results than others.
• Increased coefficient of variation noted between 2019 and 2020/2021, correlating with method changes.
• Variable performance of semi-quantitative PCT methods at low and high concentrations.

Conclusions:

• Procalcitonin (PCT) assay performance is not uniform across manufacturers, necessitating assay-specific validation.
• Clinical decision cut-offs for PCT require validation for each assay to ensure reliable sepsis management.
• Further studies are needed to determine the commutability of external quality assurance program materials.