Laboratory Test DirectoryShare
Measurement of calcium is used in the diagnosis and treatment of parathyroid disease, a variety of bone diseases, chronic renal disease and tetany (intermittent muscular contractions or spasms). Although more than 99% of body calcium exists in bones and teeth, it is the calcium in blood that is of most concern clinically.
In disease, calcium concentration may be either higher or lower than normal. Normal levels are highest in children and decline gradually throughout life. Variations in serum calcium may be due to disease of the parathyroid gland, bone disease, defective absorption of calcium from the intestine, kidney disease, multiple myeloma and various other abnormalities.
Calcium Arsenazo procedure is based on calcium ions (Ca2+) reacting with Arsenazo III (2,2’-[1,8-Dihydroxy-3,6-disulphonaphthylene-2,7-bisazo] bisbenzenearsonic acid) to form an intense purple colored complex. Magnesium does not significantly interfere in calcium determination using Arsenazo III. In this method the absorbance of the Ca-Arsenazo III complex is measured bichromatically at 660/700 nm. The resulting increase in absorbance of the reaction mixture is directly proportional to the calcium concentration in the sample.
Collect: Serum Separator Tube (SST)- 0.5 ml
Specimen preparation: Serum free from hemolysis is the recommended specimens. Allow blood samples to clot (15 mins). Separate the serum from the cells by centrifuging for 10 minutes. Store serum at 2-8°C until analysis.
Stability: Serum calcium is stable in serum for one week at room temperature (18 - 25°C), approximately 22 days refrigerated at 2-8°C, and up to 1 year frozen at <-20°C.
At Accu Reference: Refrigerated -7 days: Frozen- 1 month
NOTE: * This test is approved for all states. *
Accu Reference Medical Laboratory
Adults: 8.6 - 10.5 mg/dL
The assay Reportable Range is from 4.0 to 18.0 mg/dL. Samples exceeding the upper limit of linearity are diluted and repeated.