Retrospective Approach to Evaluate Interferences in Immunoassay

Area of Science:

• Clinical Chemistry
• Immunology
• Laboratory Medicine

Background:

• Analytical interference in immunoassays remains a significant concern despite advancements in technology.
• Interfering substances, including endogenous compounds and antibodies, can cause false positive or negative immunoassay results.
• Such interferences can lead to misinterpretation of patient reports and inappropriate treatment decisions.

Purpose of the Study:

• To retrospectively assess the prevalence and types of analytical interferences encountered in routine immunoassay practice.
• To investigate the impact of interfering substances on various immunoassay parameters.

Main Methods:

• A retrospective analysis of 42 clinically discordant immunoassay samples over six months.
• Samples were reanalyzed after treatment with antibody blocking agents and diluents to identify interference.
• Evaluation included parameters such as Beta HCG, Estradiol, CA 125, AFP, prolactin, Hepatitis B Surface antigen, and troponin I.

Main Results:

• Out of 42 samples, 19 (45%) exhibited interferences.
• Specific interferences were noted for Beta HCG (6 samples), Estradiol (3), CA-125 (3), AFP (2), prolactin (1), Hepatitis B Surface antigen (1), and troponin I (2).
• Both positive and negative interferences were observed across different analytes.

Conclusions:

• Endogenous substances can interfere with immunoassay analyses, even with advanced laboratory equipment.
• Thorough evaluation of immunoassay reports is crucial in cases of suspected interference to ensure diagnostic accuracy.
• Continuous vigilance and investigation of interferences are necessary for reliable clinical laboratory practice.