Spurious Results due to Inappropriate Collection/Storage

Problem Common Causes Consequences
Delay is separation of serum overnight storage
delay in transit
Increased K+, PO4, ALT, LDH
Decreased HCO3, (Na+ occasionally)
Storage storing at 4oC Increased K+
Decreased HCO3
Haemolysis expelling blood through needle into tube
over vigorous mixing of specimen
storing specimen in freezer
excessive delay in transit
leaving specimen in hot environment
Increased K+, PO4, Bilirubin, LDH
Decreased Na+, Cl-, Glu
Inappropriate sampling site specimen taken from drip arm Increased drip analyte, e.g. glucose, K+, Mg2+
Dilutional effect
Incorrect container or anticoagulant no enzyme inhibitor
EDTA tube (purple or grey tube) or transferring blood form one tube to another
Low glucose
Increased K+
Decreased Ca2+, ALP, Mg2+
Lipaemia specimen taken after a fatty meal Decreased Na+