Accuracy-Based Proficiency Testing Surveys for Testosterone Provide Important Information About Measurement Accuracy...

Area of Science:

• Clinical chemistry
• Laboratory medicine
• Diagnostic accuracy

Background:

• Clinical guidelines rely on accurate laboratory measurements.
• Inter-laboratory accuracy is crucial for consistent patient care.
• Testosterone measurement accuracy is vital for diagnosing hypogonadism.

Purpose of the Study:

• Evaluate commutable specimens as surrogates for accuracy across testosterone testing platforms.
• Assess miscategorization errors near the male hypogonadal threshold.
• Determine if traditional survey performance predicts commutable specimen performance.

Main Methods:

• Three serum samples (A, B, C) were prepared as commutable specimens.
• Samples were distributed via traditional (non-commutable) and accuracy-based (commutable) proficiency testing surveys.
• Laboratory testosterone measurements were analyzed against reference values.

Main Results:

• Overall mean bias was <2%, but individual method group biases ranged -16% to +15%.
• Significant miscategorization occurred near the hypogonadal threshold (5% false negatives for Sample A, 44% false positives for Sample B).
• Bias direction and magnitude differed between commutable and non-commutable specimens for 3 of 6 method groups.

Conclusions:

• Performance assessment using commutable specimens from fewer labs can approximate general method group performance.
• Commutable specimens are valuable for identifying potential diagnostic errors.
• Standardized accuracy-based surveys are essential for reliable laboratory testing.