Performance of quantitative urine analysis in Australasia critically assessed

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Urine Analysis Quality Assurance

Background:

• Quantitative urine analysis is crucial for diagnosing and monitoring various medical conditions.
• Interlaboratory quality assurance programs are essential for maintaining high standards in diagnostic testing.
• Previous assessments indicated variability in urine assay performance across Australasian laboratories.

Purpose of the Study:

• To evaluate the precision and accuracy of routine quantitative urine assays in Australasia.
• To identify specific assays and methods that require improvement.
• To provide recommendations for enhancing the quality of urine analysis.

Main Methods:

• A national interlaboratory quality-assurance program was conducted over three years (1984-1986).
• Fourteen different urine assays were investigated, assessing individual methods and measurement systems.
• Data on precision and accuracy were collected and analyzed for each assay.

Main Results:

• Assays for sodium, potassium, creatinine, glucose, and chloride demonstrated satisfactory performance.
• Urinary osmolality, phosphate, and 5-hydroxyindoleacetic acid assays require further improvement.
• Urinary protein and urate assays presented significant challenges, with the sulfosalicylic acid method for protein showing poor precision and bias.

Conclusions:

• While some urine assays meet acceptable standards, significant improvements are needed in specific areas, particularly protein and urate analysis.
• The sulfosalicylic acid turbidimetric method for urinary protein should be discontinued due to consistent poor performance.
• The trichloroacetic acid-Ponceau S manual method is a reliable alternative for urinary protein determination.