Outline of Today’s lecture
1. Introduction
2. Distribution of calcium
3. Calcium functions
4. Sources of calcium
5. Clinical significance of calcium
6. Principle of calcium estimation
Objectives
 To determine serum calcium level.
 Master how to determine the conc. of calcium in
serum.
 Discuss calcium functions.
 Discuss the hypercalcaemia and hypocalcaemia
Introduction
Calcium is the most common mineral in
the human body.
Calcium has a lot of cellular and tissue
effects involving contractile machinery,
structural roles, enzymatic reactions etc.
Calcium found in the blood and fluid must
be
maintained
within
a
narrow
concentration
range
for
normal
physiological functioning.
Distribution of Ca
99% of calcium in the body is part of bone .
1% in the blood :
- 45% circulates as free Ca ions.
- 40% bound to albumin.
- 15% bound to anions.
► Both total calcium and ionized calcium
measurements are available in many laboratories.
Physiological functions of Calcium
Bone mineralization.
Blood coagulation.
Important in muscle contraction.
Affecting enzyme activity.
Affecting hormone secretion.
Sources of Calcium
Excellent sources include milk products
– Skim milk, low-fat cheese, nonfat yogurt
Other good sources include
– Green leafy vegetables (kale, collard greens,
broccoli, and cabbage are low in oxalates)
– Others like orange juice, soy milk
– Fish with edible bones (sardines, salmon)
12-
Structure : calcium is a major
structural element in bones and teeth.
Cell signaling:
– Constriction and relaxation of blood
vessels.
– Nerve impulse transmission.
– Muscle contraction.
– Secretion of hormones
3-
Cofactors for enzymes and proteins:
A-Hypercalcaemia (high serum calcium)
1-Hyperparathyrodism.
2-Carcinoma (Cancer) Metastatic To Bone
3-Sarcoidosis.
4-Multiple Myeloma
B-Hypocalcaemia (low serum calcium)
1-Pseudohypoparathyrodism.
2-Vitamin D Deficiency.
3-Malabsorption.
4- Kidney Disease.
stones, bones, abdominal groans and psychiatric moans
(renal stones, peptic ulcers, pancreatitis, confusion,
lethargy, weakness)
Calcium ions react with reagent (ocresolphthalein-complexone) in an alkaline
medium to form a purple colored complex.
The absorbance of this complex is
proportional to the concentration in the
sample
Requirements
Requirements:
Automatic pipettes
Tips
Cuvettes
 Spectrophotometer
 Reagent
Specimen:
Serum or plasma
Preparation of Cuvettes
Procedure
Blank
(only Reagent)
Standard
(Reagent+ Calcium St.)
Sample
(Reagent+Serum)
Reagents
Calcium Standard (μl)
Sample # 1 (μl)
Ca++ reagent (ml)
Blank
-
Std.
20
S#1
-
-
-
20
1.0
1.0
1.0
Mix, wait 5 minutes at room temperature
(RT).
Zero the spectrophotometer with the blank
at 570 nm.
Read the absorbance for both of standard
and the samples.
Record your results for further calculation.
The color is stable for at least 45 minutes.
Calcium concentration (mg/dl)=
Absorbance of Sample
Absorbance of Standard
X Standard Conc.
Child
2.20-2.70 mmol/L (8.8-10.8 mg/dL)
Adult
2.15-2.50 mmol/L (8.6-10.0 mg/dL)
Conclusion
Calcium is essential!!!
An important mineral for human health
Must meet adequate daily intake in
order to maintain a healthy skeleton
A very exciting area for research