Factor XI assay results in the CAP survey (1981)

Area of Science:

• Clinical Chemistry
• Hematology
• Laboratory Medicine

Background:

• Factor XI assays are crucial for diagnosing bleeding disorders.
• The 1981 College of American Pathologists (CAP) Survey assessed factor XI assay performance.
• Variability in laboratory practices can impact diagnostic accuracy.

Purpose of the Study:

• To evaluate the precision and sensitivity of various factor XI assay systems.
• To analyze laboratory practices and identify sources of interlaboratory variation.
• To determine the need for standardization in factor XI assays.

Main Methods:

• Review of data from the 1981 CAP Survey for factor XI assay.
• Ranking of instrument-reagent combinations based on precision and sensitivity.
• Analysis of survey questionnaire responses regarding laboratory procedures.
• Comparison with recent CAP surveys for factor VIII and IX activity.

Main Results:

• Poor correlation observed between the precision and sensitivity of most factor XI assay systems.
• Assay precision tended to decrease with increasing severity of factor XI deficiency.
• Significant interlaboratory variations were noted in technical aspects, including standard curve construction.
• Specimen handling procedures, like freezing, may impede the identification of mild factor XI deficiencies.

Conclusions:

• Current factor XI assay methods exhibit significant variability and limitations.
• Standardization of factor XI assay procedures is essential for reliable diagnostic results.
• Improved laboratory practices are needed to enhance the accuracy of factor XI deficiency detection.