Summary Pre-analytic, Analytic, and Post-analytical Variable Affecting Specimen Collection

Pre-analytical Variables Analytical Variables Post-analytical Variables
Affecting Specimen Collection Affecting Specimen Collection Affecting Specimen Collection


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Identify areas to avoid in site ~
Venous stasis ~
Time before separation from cell
selection like infected sites, (for plasma).
hematoma, etc. ~
Tube type ~
Ex: decrease glucose when stored
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Serum in EDTA Whole blood.
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Diet restrictions like fasting ~
EDTA
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Heparin and Fluoride ~
Centrifugation conditions
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Drug restriction or medication
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Side effects ~
Order of draw ~
Special separation requirements
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Recreational substances
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Hemolysis should be avoided ~
Division of sample into sufficient
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Common error: overlook witholding number of aliquots of a sufficient
steroids for at least 8 hours prior to ~
Collection volume volume.
Synacthen test. Sufficient = correct Decrease aliquot = decrease result
concentration of additives.
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Lifestyle ~
Temperature and time between
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Smoking ~
Stress separation and analyses. Complete
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Alcohol ~
Fainting of patient thawing, adequate mixing and
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Stress-responsive hormones centrifugation of foreign samples
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Physiological before analyses.
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Posture: Blood volume, bp, heart ~
Labeling
rate ~
Specially when collecting
multiple samples.
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Medical Conditions
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Pregnancy
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Stress
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Fever
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