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Test Code APTT Pro Mix APTT Prolonged (Mixing Study) w Reflex

Patient Preparation

No special patient preparation required

Special Collection Instructions

Properly filled 9:1 ratio (blood to anticoagulant); 3.2% NaCitrate tube

Collection Method

Venous Draw; properly filled 9:1 ratio (blood to anticoagulant)

Minimum Volume

1.5 mL of plasma from properly filled 1.8 mL or 2.7 mL NaCitrate (light blue) tubes

Container

Light Blue Sodium Citrate
 

Preferred Specimen

Three 2.7mL Lt. Blue (3.2% NaCitrate) tubes

Acceptable Specimens

Three 1.8 mL Lt. Blue (3.2% NaCitrate) tubes

Reference or Target Ranges

See PT, PTT and Thrombin time for normal ranges 

Reportable Units

Seconds

Critical Value

>150 Seconds

Reasons for Rejection

Hemolysis Threshold Gross Hemolysis
Icterus Threshold Gross Icterus
Lipemia Threshold Gross Lipemia
Interfering Subtances/Other Short draws, over draws, clotted, improperly labeled

Specimen Stability

Ambient 4 hours whole blood
Refrigerated (4°C to 8°C) N/A
Frozen(-70°C to -20°C) 2 Weeks@ -20°C; 1 year @ -70°C

Performance Information

Initial PT, PTT, and Thrombin Time:  
Days and Time Performed 24/7
Expected Turn Around Time Routine: within 4 hours of arrival to lab
Stat Availability within 1 hour of arrival to lab
Performing Bench Coagulation
Methodology/Method Description Werfen ACL TOPS Photometric detection system.

Turnaround time for any reflexed tests will extend over several days due to batched analyses of specialty tests or referral to external laboratories

Useful For

Used for the evaluation of unexplained prolongation of APTT and intended for use when coagulation factor deficiencies or inhibitors are suspected. Initial testing includes PT, aPTT, and thrombin time. Additional specialized coagulation studies such as factor assays, lupus anticoagulant panel, von Willebrand panel, or mixing studies will be selected by coagulation-trained pathologists, taking into account clinical context such as bleeding history and anticoagulant use. 

CPT Codes

85732 x2

Reflex Testing

Determined by pathology. Possible reflex testing can include Lupus anticoagulant panel, von Willebrand Screening Panel, factor assay levels, mixing studies, or other specialized coagulation testing as determined by pathologists review.