Calcium Flashcards
Calcium is associayed with
Blood coagulation
Enzyme activity
Excitability of skeletal and cardiac muscle
Maintenance of blood pressure
Calcium play essential role in
Intracellularly (muscle contraction, glycogen metabolism)
Extracellularly (bone mineralization and blood coagulation)
Calcium is present in plasma in three forms
Free
Bound to proteins
Complex with anions as phosphate, citrate and bicarbonate
Decreased total calcium levels
Bone apparatus (osteoporosis)
Kidney disease (under dialysis)
Defective intestinal absorption
Hypoparathyroidism
Increased total calcium
Hyperparathyroidism
Malignant disease with metastases and sarcoidosis
Method for calcium
Photometric test using arsenazo III
Calcium principle
Calcium with arsenazo III at neutral pH yields a blue colored complex, whose intensity is proportional to the calcium concentration. Interference by magnesium is eliminated by addition of 8-hydroxyquinoline-5-sulfonic acid.
Calcium Reagents
Phosphate buffer pH 7.5 50 mmol/L
8-Hydroxyquinoline-5-sulfonic acid 5 mmol/L
Arsenazo III 120umol/L
Stored
2-8 degree celcius
Wavelength calcium
650 nm
Conversion factor to mmol/L
0.2495
Convertion factor per 24 hour
0.025
Interference calcium
Strontium salts in medicine may lead to strongly increased calcium values.
Reference range calcium
Serum/ Plasma- 8.6 – 10.3 mg/dL (2.15 – 2.57 mmol/L)
Urine [1]:
Women < 250 mg/24 h (6.24 mmol/24 h) Men < 300 mg/24 h (7.49 mmol/24 h)
Calcium hormones
1,25- Dihydocholecalciferol
Parathyroid hormone
Calcitonin
