| Test Name: | Activated Partial Thromboplastin Time (APTT) |
| Epic Order Code: | LAB325 | | |
| CPT Code: | 85730 |
| Specimen(s) Type: | Plasma; Full tube is required. |
| Acceptable Container(s): |  Top is light blue |
| Testing Schedule: | 24 hrs/day, 7 days/week |
| Turn Around Time: | STAT: 1 hour |
| | Routine: 4 hours |
| Collection Information: | No special patient preparation is required. Obtain specimen by standard collection procedures. If only APTT is being collected, draw 5 mL into a red top tube, discard and then collect APTT tube. A full tube is required. |
| Transport Information: | Deliver to lab immediately. All specimens must be signed into the laboratory. |
| Reference Clients: | If unable to deliver to the lab within 1 hour, centrifuge the specimen for 10 minutes at 3500 RPM to ensure platelet poor plasma. Remove plasma from cells, taking care to avoid the WBC/platelet buffy layer and place into a transport tube. Store and transport at room temperature for up to 4 hours. If testing is delayed beyond this, the sample must be stored and transported frozen at -20° C and delivered to lab within 2 weeks. |
| Causes for Rejection: | Improperly labeled, incorrect container, contaminated, insufficient quantity, incorrect/delay in transport, grossly hemolyzed, clotted, under or over-filled tube. |
| Reference Range: | Automated: 24.5-34.0 seconds |
| | Manual: 23.4-35.1 seconds |
| | Critical: > 69.9 seconds |
| | Be sure to check the reference range on the patients report for a change in the reference range that may occur when a new lot of APTT reagent is used. |
| Additional Information: | Collection of blood for coagulation testing through intravenous lines that have been previously flushed with heparin should be avoided, if possible. If the blood must be drawn through an indwelling catheter, possible heparin contamination and specimen dilution should be considered. When obtaining specimens from indwelling lines that may contain heparin, the line should be flushed with 5 mL saline, and the first 5 mL of blood or 6 times the line volume (dead space volume of the catheter) be drawn off and discarded before the coagulation tube is filled. For those samples collected from a normal saline lock (capped off venous port) twice the dead space volume of the catheter and extension set should be discarded. |