Microdetermination of serum calcium by parallel fast analyzer

Area of Science:

• Clinical Chemistry
• Analytical Biochemistry

Background:

• Accurate serum calcium measurement is crucial for diagnosing various medical conditions.
• Existing methods may require larger sample volumes or specialized equipment.

Purpose of the Study:

• To describe an adapted direct microdetermination method for serum calcium.
• To evaluate the method's suitability for parallel fast analyzers and its clinical accuracy.

Main Methods:

• Utilized a colored reaction product of serum calcium with cresolphthalein complexone.
• Employed a microdetermination technique requiring only 20 microliters of sample.
• Validated against atomic absorption spectroscopy.

Main Results:

• Achieved a high correlation coefficient (r=0.94) with atomic absorption.
• Demonstrated low inter-day coefficients of variation (2.3-3.2%).
• Established normal ranges for adult males (8.5–10.8 mg/dL) and females (8.5–10.5 mg/dL).

Conclusions:

• The adapted method is simple, reliable, and clinically accurate for serum calcium determination.
• The microtechnique is efficient, requiring minimal sample volume.
• Potential interferences from hemolysis, jaundice, and lipemia were noted, requiring careful sample handling.