Permanent, long-term and short-term acting factors on the biological variation of the results – examples.
Factors, influencing the laboratory result
- Pathological factors
- Biological factors –biological variation
- Factors in the preanalytical stage: conditions of specimen collection, transport and storage of the biological material; diagnostic and therapeutically procedures
- Analytical factors-analytical variation
- Postanalytical factors
Constant: sex (diff level of RBC, WBC, hormones, cholesterol), race (diff races have certain diff genetics).
short term: depending what time of the day it is (different minerals at diff levels during diff parts of day), menstruation, physical activity, stress (^ adrenaline and cortisol), fasting, position of body (upright position causes a reduction of plasma volume and increased concentration of proteins), vein stasis (slow blood movement in veins
Example: STRESS It leads to elevated levels of adrenalin, increased cortisol and glycogenolysis. Hyperventilation influences the parameters of the acid-alkaline balance
long term: age, weight, muscle mass (more weight means more cholesterol, protein, creatinine, uric acid), way of living, pregnancy (^cholesterol and WBC, ˅ minerals and protein), diet (protein increases urea, fats increase TAG), climate (affect haemoglobin, RBC, coagulation), season, environment
Errors in the preanalytical stage – preparing the patient; proper time, strict adherence to proper technique of collection of the specimen; identification of the patient and the specimen; transport and storage,
Errors in the analytical stage: – method, calibration, chemicals and reagents, instruments, qualification of the staff
Errors in the postanalytical stage– wrong estimations; exchange specimen/result; incorrect interpretation;