Factors interfering with analysis
Haemolysis
Haemolysis is caused by leakage of intracellular components of the erythrocytes such as phosphate, iron, potassium and especially haemoglobin due to a damage of the cell membrane. Haemoglobin causes a red colouration of serum/plasma which primarily interferes with the photometric testing done in clinical chemistry.
Lipaemia
Lipaemia refers to the milky/turbid discolouration of serum/plasma due to triglycerides. It is mostly caused by diet- or stress-related factors. Lipaemia can also occur as a result of endocrinological diseases like Cushing’s syndrome or hypothyroidism.
Lipaemic samples often complicate the measurement of certain clinical parameters, e. g. bilirubin.
Icterus
Icterus is a yellowish discolouration of serum/plasma. Excess amounts of bilirubin, which is the reason for the yellow colouring, are normally caused by a medical condition and cannot be influenced.
The yellow colouration is physiological in horses.
Interfering factor | Parameter | Level |
Haemolysis | LDH, CK, AST, bilirubin, AP, creatinine, PO4, K, Mg, Fe, fructosamine | elevated |
Haemolysis | Ca, glucose | lowered |
Lipaemia | ALT, AST, AP, bilirubin, glucose, Ca, PO4, total protein, lipids, haemoglobin | elevated |
Lipaemia | albumin, amylase, Na, CI, K | lowered |
Icterus | AP, total protein, Cl, PO4 | elevated |
Icterus | triglycerides, creatinine, Mg | lowered |
Drug | Parameter | Level |
Penicillin G | K | elevated |
Tetracyclines | PO4 | elevated |
Tetracyclines | K | lowered |
Salicylates | CK, AP, glucose, Na, total protein | elevated |
Salicylates | K, Ca | lowered |
Corticosteroides | CK, AP, glucose, Na, total protein | elevated |
Corticosteroides | K, Ca | lowered |
Phenylbutazone | Ca, Na | elevated |
Barbiturates | CK | elevated |
Halothane anaesthesia | CK, PO4 | elevated |
Glucose infusion | glucose | elevated |
Glucose infusion | PO4 | lowered |
