 Measurements should be performed within 45 mins to 1 hr after collection

 Serum or Plasma: separated w/in 1hr

 3000 RCF for 10 mins: centrifugation requirement

a. To prevent glycolysis

∞ 2mg NaF/mL of blood – prevents glycolysis for up to 48-72 hours

∞ Glucose conc in unseparated serum or plasma- decreases rapidly in the first 24 hours

b. Certain substances are very unstable

∞ increase in: total bilirubin, sodium, urea, nitrogen, albumin, calcium, magnesium and total protein

c. To prevent shift of electrolytes

∞ results in: false increase of potassium and decrease of sodium in serum/plasma

d. To prevent hemolysis

∞ Increased enzymes (LD, ACP, ALT, AST); electrolytes (Mg, P, K); TP; albumin; cholesterol and iron

∞ Interferes with the color reactions

∞ Increases bilirubin levels