An interlaboratory comparison of serum total protein analyses

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Analytical Chemistry

Background:

• The College of American Pathologists (CAP) Comprehensive Chemistry Survey is a vital tool for laboratory quality assessment.
• Accurate measurement of total serum proteins is crucial for diagnosing various medical conditions.

Purpose of the Study:

• To analyze the data from the 1976 CAP Comprehensive Chemistry Survey regarding total serum protein measurements.
• To evaluate the precision and accuracy of different analytical systems and methods used for total serum protein estimation.

Main Methods:

• Analysis of data contributed by over 2,000 laboratories participating in the 1976 CAP survey.
• Evaluation of total serum protein concentration using the biuret reaction and refractometry as primary methods.
• Assessment of precision and accuracy data across various analytic systems.

Main Results:

• The biuret reaction was the most prevalent method for total serum protein estimation, followed by refractometry.
• Precision among participating laboratories was found to be generally comparable across different analytical systems.
• A notable finding was a negative bias in total protein concentration measurements reported by the SMAC system.

Conclusions:

• The biuret method remains a widely adopted and reliable technique for total serum protein analysis.
• While overall precision is good, specific analytical systems like SMAC may introduce biases that require attention.
• The survey highlights the importance of continuous monitoring and evaluation of laboratory methods for accurate patient diagnosis.