Table 1 Artefactual results

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Artefactual results due to problems in specimen collection/handling or to pathological conditions

Na

K

Total Ca

Albumin

Phosphate

Creatinine

LD

ALP

AST

Glucose

Lipids

APTT/PT

Haemoglobin /PCV

WCC

Platelet count

Prolonged venous stasis during collection (tourniquet)

-

-

Increased

Increased

-

-

-

-

-

-

Increased

May be shortened

Increased

Increased

Increased

Sample collected proximal to infusion (as indicated)

Increased (saline) Decreased (dextrose)

Increased (KCl) Decreased (other)

Decreased

Increased (plasma, albumin) Decreased (other)

Decreased

Decreased

Decreased

Decreased

Decreased

Increased (dextrose) Decreased (other)

Increased (TGs with Intralipid) Decreased (other)

Prolonged (heparin)

Decreased

Decreased

Decreased

Difficult or traumatic collection

-

Increased

-

-

-

-

Increased

-

Increased

-

-

May be shortened, prolonged

Decreased (may be small clot in sample)

Decreased (may be small clot in sample)

Decreased (may be small clot in sample)

Use of incorrect anticoagulant (as indicated)

Increased (Na2 EDTA or sodium citrate)

Increased (K2 EDTA)

Decreased (EDTA, citrate or oxalate)

-

-

-

-

Decreased (EDTA)

-

-

-

Prolonged (EDTA or heparin)

-

-

Decreased (heparin)

Too little blood added to anticoagulant

-

Increased (if marked discrepancy)

-

-

-

-

-

-

-

-

-

Prolonged

Artefactual changes in cell morphology, on blood film

Artefactual changes in cell morphology, on blood film

Artefactual changes in cell morphology, on blood film

Too much blood added to anticoagulant

-

-

-

-

-

-

-

-

-

-

-

May be shortened, prolonged

Decreased (may be small clot in sample)

Decreased (may be small clot in sample)

Decreased (may be small clot in sample)

Prolonged storage or refrigeration of whole blood

Decreased (RT or 4oC)

Increased (RT or 4oC)

-

-

Increased (RT)

-

Increased (RT or 4oC)

-

Increased

Decreased (RT)

-

Prolonged (RT or 4oC)

Artefactual changes in cell morphology, on blood film

Decreased Artefactual changes in cell morphology, on blood film

Decreased Artefactual changes in cell morphology, on blood film

Extreme leucocytosis

-

Increased

-

-

-

-

Increased

-

-

Decreased

-

-

Hb may be increased

-

-

Extreme thrombocytosis

-

Increased

-

-

-

-

Increased

-

-

Decreased

-

-

-

-

-

Marked erythrocytosis

-

-

-

-

-

-

-

-

-

Decreased

-

Prolonged

-

-

-

Marked lipaemia

Decreased

-

Possible interference with assay

Possible interference with assay

Possible interference with assay

Possible interference with assay

Possible interference with assay

Possible interference with assay

Possible interference with assay

Interference with assay

-

Interference with automated methods

Hb may be increased

-

-

Marked hyper- globulinaemia

Decreased

-

Decreased

-

-

-

-

-

-

-

-

-

Hb may be increased

-

-

Marked jaundice

-

-

-

-

-

Decreased (some methods)

-

-

-

Decreased (some methods)

-

-

-

-

-

Comments relate to potentially clinically significant effects

RT denotes room temperature: approx. 22^oC

TGs denote triglycerides