Calcium is the most abundant and one of the most important minerals in the
human body. Approximately 99% of body calcium is found in bones. A
decrease in albumin level causes a decrease in serum calcium.
Among causes of hypercalcemia are cancers, large intake of vitamin D,
enhanced renal retention, osteoporosis, sarcoidosis, thyrotoxicosis,
hyperparathyroidism.
Low levels of calcium are found in hypoparathyroidism,
pseudohypoparathyroidism, vitamin D deficiency, malnutrition and intestinal
malabsoprtion1,6,7.
Clinical diagnosis should not be made on a single test result; it should
integrate clinical and other laboratory data.
STORAGE AND STABILITY
All the components of the kit are stable until the expiration date on the label
when stored tightly closed at 2-8ºC, protected from light and contaminations
prevented during their use.
Do not use reagents over the expiration date.
Signs of reagent deterioration:
- Presence of particles and turbidity.
- Blank absorbance (A) at 570 nm 0,22.
ADDITIONAL EQUIPMENT
- Spectrophotometer or colorimeter measuring at 570 nm.
- Matched cuvettes 1,0 cm light path. - General laboratory equipment (Note 2,3).
SAMPLES
- Serum or plasma1: Separated from cells as rapidly as possible. Blood
anticoagulants with oxalate or EDTA are not acceptable since these
chemicals are strong calcium chelators.
- Urine1: Collect 24 hour urine specimen in calcium free containers. The
collecting bottles should contain 10 ml of diluted Nitric acid (50% v/v).
Record the volume.
Dilute a sample 1/2 in distilled water. Mix. Multiply results by 2 (dilution factor).
Stability of the samples: Calcium is stable 10 days at 2-8ºC.