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Calcium Ions (Ca2+) react with Arsenazo III to form a purple complex. The absorbance of the Ca-Arsenazo III complex is measured biochromatically at 660/700 nm. The increase in absorbance of the reaction mixture is directly proportional to the calcium concentration in the sample.

Test Utility

Calcium measurement aids in the diagnosis and management of several diseases involving the parathyroid glands, pancreas, kidneys, gastrointestinal tract, bones and endocrine system.

Specimen Collection and Preparation

Sample should be centrifuged at 3000 rpm for 15 minutes within 1 hour of collection, and plasma separated as soon as possible.

Serum or plasma sample in the following tubes:

  • Serum separator tube (gold or tiger top)

  • Lithium Heparin (green top)

Specimen Storage and Stability

Store serum or plasma at the following temperatures:

  • Room temperature: 15°C to 30°C up to 7 days

  • Refrigerated: 2°C to 8°C up to 22 days

  • Frozen: -20°C or lower up to 1 year

Specimen Rejection

  • Insufficient sample volume

  • Sample not stored at proper temperature

  • Frozen whole blood

  • Hemolyzed samples

  • Severely lipemic specimens

  • Specimen labeled incorrectly or not labeled

Reference Pages


Monday – Saturday

Result available within 24 hours of receipt in laboratory

NOTE: Specimens are refrigerated (2-8°) for 7 days before disposal


Vibra Health Laboratory

1307- A, Allen Dr

Troy, MI 48083

(248) 846-0663

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