Current Practices When Reporting Quantitative Human Chorionic Gonadotropin Test Results.

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Reproductive Endocrinology

Background:

• Quantitative human chorionic gonadotropin (hCG) tests are crucial for determining pregnancy status.
• Laboratory reporting practices for hCG results lack standardization and have not been previously investigated.

Purpose of the Study:

• To investigate the current reporting practices for quantitative human chorionic gonadotropin (hCG) tests across clinical laboratories.
• To identify variations in reference intervals, cutoffs, and result interpretations used in hCG testing.

Main Methods:

• A voluntary questionnaire was distributed to 6433 laboratories participating in a general chemistry proficiency testing survey.
• Responses from 3568 laboratories were analyzed to assess reporting methodologies for quantitative hCG.

Main Results:

• Significant variation exists in hCG reporting: 31% used a single cutoff, with 5.0 IU/L being common. Only 9% offered chronological age-based intervals, while 60% used gestational age-based intervals.
• Most laboratories (68%) provided qualitative interpretations (e.g., "positive," "negative"). Few (12%) offered hCG as a distinct tumor marker test.
• Nearly half of laboratories relied on assay product insert data for reference intervals, highlighting a lack of standardized internal validation.

Conclusions:

• Wide variations in quantitative hCG reporting practices, including cutoffs and reference intervals, are prevalent.
• Current practices deviate from established guidelines (e.g., <5.0 IU/L for nonpregnant status), impacting result consistency.
• Development of data-driven guidelines is recommended to standardize quantitative hCG reporting and improve clinical interpretation.