Pathology Information Clinical Chemistry Telephone Action Limits

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 4^oC 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⁺

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 4^oC	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⁺