Stability of HE4 and CA125 in blood samples from patients diagnosed with ovarian cancer

Abstract

Objective. To investigate the influence of handling and storage on HE4 and CA125 serum and EDTA plasma levels to clarify any important consequences for a clinical setting. Methods. Blood samples from 13 ovarian cancer (OC) patients were collected and allowed to clot or sediment for up to 72 hours at 4°C or 20°C, then processed into serum and EDTA plasma. Furthermore, the effects of up to eight repetitive cycles of freeze/thaw were investigated. HE4 and CA125 were analyzed using a Chemiluminescent Microparticle Immunoassay on the Architect i2000sr System. Results. No significant effect of processing time for HE4 could be shown. HE4 EDTA plasma levels were insignificantly lower (3%) than serum levels (p = 0.41). Similarly, no significant effect of processing time for CA125 could be demonstrated. CA125 levels at 4°C were significantly reduced compared to levels at 20°C (p = 0.024). No significant difference between CA125 serum and plasma levels were found (p = 0.46). Serum and EDTA plasma samples were stable during the eight cycles of freezing and thawing (CA125: all p > 0.2; HE4: all p > 0.5). Conclusion. No systematic difference could be demonstrated for HE4. CA125 is not dependent on processing time, EDTA plasma or serum. Levels of CA125 are significantly reduced at 4°C compared to levels at 20°C, but this difference was less than 6% and is not considered clinically relevant.

Key Words::

• Biomarker
• cancer antigen 125
• chemiluminescent immunoassay
• EDTA plasma
• Human epididymis protein 4
• serum
• specimen handling

Acknowledgements

Abbott GmbH & Co. KG, Germany, provided study reagents for this study.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.