PARTIAL THROMBOPLASTIN TIME (aPTT), PLASMA
test app
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Specimen Type:
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Whole blood
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Container/Tube
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Preferred:
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Light blue-top (Citrate) Vacutainer®.
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Acceptable:
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Blue-cap (9CL/1.3) microtainer (contact lab at 314-454-4268 if micro tube required).
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Collection Volume:
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Vacutainer® should be full (to
markings on tube label. MINIMUM tube volume for collection is to marking on tube
label, but may go above line.)
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Patient Preparation:
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None
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Sample Rejection
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Vacutainer®(s) that are under-filled.
Clotted
specimens.
Grossly hemolyzed specimens.
Mislabeled or unlabeled specimens.
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Special Instructions:
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1.
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Draw a discard tube prior to
light-blue top tube
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2.
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Tube(s) should remain
stoppered.
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3.
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Immediately invert
tube/microtainer® gently 8-10 times after
collection to ensure proper mixing of blood and anticoagulant
(this will avoid specimen clotting).
Forward promptly at ambient temperature
only.
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4.
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DO NOT underfill
tube(s)
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5.
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SPECIMEN MAY NOT BE COLLECTED BY CAPILLARY
METHOD
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6.
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If the patient has a known hematocrit >55%,
contact the lab at 454-4268 for collection instructions and a specially adjusted
collection tube(s).
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Day(s) Test Set Up:
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Monday-Sunday
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Cut-off time:
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None; performed as received
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Turnaround Time:
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Same day; 1 hour from receipt in
lab
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Lab Testing Section:
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Coagulation |
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Reference Range:
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<1 year:
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25-45 seconds
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1 year-10 year:
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25-40 seconds
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>= 10 Year:
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27-37 seconds
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Heparin therapeutic range: 60-94 seconds. Based on
correlation with therapeutic heparin activity range of 0.3-0.7
units/mL
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Critical Values:
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Critical value (automatic callback): >150
seconds
Critical test results will be called initially and every
72 hours thereafter.
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Limitations:
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NA
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Methodology:
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Absorbance measurement, clot signature
formation |
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Lab Processing instructions:
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Give specimen to coagulation bench to be spun in STAT Spin
centrifuge for 3 minutes @ 8500 rpm
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Processed Volume:
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Blood level should be to line on label (may be
over).
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Analyte Stability:
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Ambient: 4 hours
Refrigerated: 4 hours
Frozen (-20C) plasma: 1 month
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NOTES:
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Reject due to gross hemolysis, under-filled tube(s) or if
clotted specimen
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EPIC order name:
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aPTT (EPIC Test# LAB325)
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Cerner order name:
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aPTT
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CPT Codes:
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85730
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LOINC Value:
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14979-9
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Synonyms:
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Last Updated: 04/22
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Last Reviewed:
09/23
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