# Comparison Between a New PSA Assay With the Well‐Established Beckman Coulter Immunoassay: A Preliminary Report

## TL;DR

This study compares a new PSA test with an established one and finds the new test performs better at low PSA levels.

## Contribution

The study introduces and evaluates a new PSA immunoassay and compares its performance with existing methods.

## Key findings

- PSA-I showed a stronger correlation with PSA-B than PSA-A in samples with PSA below 2 ng/mL.
- All assays showed significant positive correlations with PSA-B across different PSA concentration ranges.
- The new PSA-A assay demonstrated good correlation with PSA-B, but not as strong as PSA-I at low concentrations.

## Abstract

Prostate‐specific antigen (PSA) is a critical biomarker for prostate cancer (PCa) patient clinical management. In this study, we sought to compare three different immunoassays (CLIA): Beckman Coulter Access Hybritech (PSA‐B) (reference method), Immulite 2000 PSA (PSA‐I) and the newly introduced Atellica IM PSA assay (PSA‐A). We selected serum samples from our routine clinical testing at University Hospital Federico II between April and May 2024 from 104 men with a median age of 66 years (interquartile range = 57–74). Total PSA was determined using three different assays: PSA‐B, PSA‐A and PSA‐I. A significant correlation between PSA‐B and PSA‐I assays was found for samples in the overall population (Spearman r (ρ) = 0.99, p < 0.0001). PSA‐I displayed a strong correlation with PSA‐B for values below 2 ng/mL (ρ = 0.98, p < 0.0001), for values between 2 and 10 ng/mL (ρ = 0.97, p < 0.0001) and for values above 10 ng/mL (ρ = 0.77, p < 0.0001). A significant positive correlation was found between PSA‐B and PSA‐A in the overall population (ρ = 0.97, p < 0.0001) and in stratified analyses between PSA‐A and PSA‐B for values below 2 ng/mL (ρ = 0.86, p < 0.0001), from 2 ng/mL to 10 ng/mL (ρ = 0.93, p < 0.0001) and above 10 ng/mL (ρ = 0.77, p < 0.0001). Although both PSA‐I and PSA‐A demonstrated a significant positive correlation with PSA‐B, PSA‐I displayed a significantly better correlation with PSA‐B than PSA‐A in samples with PSA below 2 ng/mL.