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Test Code LAB325 aPTT - Activated Partial Thromboplastin Time

Important Note

This test is for both screen and therapy, whether or not the patient is on anticoagulants.

aPTT specimens should be kept at room temperature and tested within 4 hours. Do not refrigerate aPTT specimens. If testing cannot be completed within the time limits above, separate the plasma into an aliquot container and freeze the specimen at  -20°C. Specimens frozen offsite should be double spun / plasma separated prior to freezing. Frozen specimens should be thawed at room temperature, remixed thoroughly, and tested immediately.

Additional Codes

CPT Code: 85730

Performing Laboratory

TidalHealth Peninsula Regional - Core Laboratory: Hematology

Specimen Requirements

Draw blood in a light blue-top (3.2% sodium citrate) tube, and send 4.5 mL of sodium citrate whole blood. Light blue-top tube must be at least 90% full for accurate results. (Clotted or hemolyzed specimen is not acceptable.) Forward promptly to laboratory.

Reference Values

Reference Range:  25-36 seconds

 

Therapeutic Range:  59-97 seconds

 

Critical values (automatic call-back)

>6 months: >120 seconds

<6 months: >50 seconds

Additional Information

Available STAT

Direct Oral Anticoagulants can prolong results for hemostatis assays.