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Test Code PTT APTT

Aliases

Partial Thromboplastin

Useful For

The activated partial thromboplastin time (PTT) is a basic coagulation screening test for the assessment of congenital and acquired deficiencies of the intrinsic and common pathways (PK, HMWK, factors XII, XI, IX, VIII, X, V, II, I)

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

0.5 ml of plasma from a properly filled 1.8 mL or 2.7 mL NaCitrate (light blue) tube

Container

Light Blue Sodium Citrate
 

Preferred Specimen

2.7mL Lt. Blue (3.2% NaCitrate)

Acceptable Specimens

1.8 mL Lt. Blue (3.2% NaCitrate) tube

Reference or Target Ranges

UH 25.1 – 36.5 seconds
WH 25.9– 35.7 seconds

 

 

Reportable Units

Seconds

Critical Value

>150 Seconds

Reasons for Rejection

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

Specimen Stability

Ambient Plasma – 4 hours – Specimens must be centrifuged within 1 hour of phlebotomy if the patient is theapeutically heparinized.
Refrigerated (4°C to 8°C) N/A
Frozen(-70°C to -20°C) 2 Weeks@ -20°C; 1 year @ -70°C

Performance Information

Days and Time Performed 24/7
Expected Turn Around Time Routine: within 4 hours of arrival to lab
Stat:within 1 hour of arrival to lab
Stat Availability Yes
Performing Bench Coagulation
Methodology/Method Description UH: Werfen ACL TOPS - Photo-optical clot-detection system
WCH: Stago Satellite - Electromagnetic mechanical clot detection system.

Additional Information/Important Notes

Platelet poor plasma must be used for this test.

CPT Codes

85730