1. BIOCHEMISTRY 285 PHL Introduction Blood Glucose

2. Blood
Blood is a connective tissue that circulates in the closed system of blood vessels
Functions:
Transportation
Regulation of acid-base balance
Regulation of body temperature
Immunity
Coagulation

3. Blood: Composition Blood Plasma Cellular Elements Water Solids :
Diffusible
- Anabolic
- Catabolic
Non-
diffusible
RBCs
WBCs
Platelets

4. Types of Samples Whole blood Plasma Serum
Water (plasma) + cells (RBCs, WBCs, platelets)
Plasma
Water + solids (e.g. glucose, urea, albumin, fibrinogen)
No cells
Serum
Serum = plasma – clotting factors

5. Centrifuging tubes
Centrifugator

6. Preparation of sample: Plasma
anticoagulant
Transfer the
clear
supernatant
to specimen
tube
Add venous blood
Mix then centrifuge
cells
Cent. tube

7. Preparation of sample: Serum
Venous
Blood
Transfer the
clear
supernatant
to specimen
tube
Allow blood to clot
(20min.)
Remove the clot
and centrifuge
cells
Cent. tube

8. Comparison Plasma Serum Anticoagulant No anticoagulant plasma serum
Contains clotting factors
Advantage: time saving
No anticoagulant
Contains no clotting factors
Advantage: less interference
plasma
serum

9. Anticoagulants Definition: Types : 1- Heparin
Anticoagulants are chemicals which prevent blood clotting
Types :
1- Heparin
MOA:
Prothrombin thrombin
Advantage: less interference with chemical tests
Disadvantage: high cost

10. Anticoagulants: cont. 2-EDTA (ethylene diamine tetraacetic acid):
MOA:
Binds to calcium
Advantage: prevents platelets clumping
3-Oxalates: (Na, K, Li, or NH4 salts)
Form insoluble complex with calcium
Disadvantage: interfere with lactate dehydrogenase
N.B Na, K salts should not be used in electrolytes determination

11. Anticoagulants: cont. 4-Citrate: 5-Na fluoride: (enzyme poison)
e.g. trisodium citrate
Used in ESR
5-Na fluoride: (enzyme poison)
Used in blood sugar determination b/c it inhibits glycolysis
N.B: it inhibits urease enzyme., therefore it should not be used in urea determination

12. Deproteinization Purposes: 1- Proteins have UV absorption
2- Proteins make the solution turbid & difficult to read
3- Determination of non-protein nitrogen & glucose
4- Use the precipitate in plasma protein determination e.g. albumin

13. Deproteinization Agents
Acids
1- Trichloroacetic acid
2- Tungestic acid
MOA:
↓ pH
proteins become cations
ppt as insoluble salts of acids
Bases
1- Zinc hydroxide
2- Cu, Ba, Cd hydroxide
-↑ pH,
proteins become anions
ppt as insoluble salts of heavy metals

14. Deproteinization Agents
Organic substances
e.g. ethanol or ether
MOA:
remove water from protein mol.