Immediate Test Change
Changes to Heparin Anti-Xa Assay (HEPASY) and PTT Incubated Mixing Study (PTTIM)
Heparin Anti Xa Assay (HEPASY)
Effective February 22, 2018
Specimen Requirements
Volume:
1 mL, platelet-poor plasma
Minimum Volume:
0.5 mL, platelet-poor plasma
Collection Container:
Light Blue Sodium Citrate Coagulation Tube
Stability
Ambient:
Centrifuge within one hour of phlebotomy and test; or freeze platelet-poor plasma within 4 hours
Refrigerated:
Unacceptable
Frozen:
2 weeks at minus 20°C
6 months at minus 70°C
Reference Range
0 – 99 Years:
Therapeutic range: 0.3 – 0.7 (standard nomogram) IU/mL
0 – 99 Years:
< 0.10 IU/mL
0 – 99 Years:
Stroke or low dose protocol: 0.2 – 0.5 IU/mL
Partial Thrombin Time (PTT) Incubated Mixing Study (PTTIM)
Effective February 22, 2018
Reference Ranges
PT Screen
0 – 1 Days:
7.9 – 14.8 sec
2 – 5 Days:
7.4 – 14.2 sec
6 – 30 Days:
7.2 – 13.3 sec
1 – 3 Months:
7.2 – 13.2 sec
4 – 11 Months:
8.3 – 12.9 sec
1 – 99 Years:
8.4 – 13.0 sec
APPT Screen
0 – 1 Days:
28.7 – 45.1 sec
2 – 5 Days:
23.3 – 49.4 sec
6 – 30 Days:
23.5 – 45.6 sec
1 – 3 Months:
22.1 – 41.4 sec
4 – 11 Months:
25.8 – 35.5 sec
1 – 99 Years:
24.4 – 33.4 sec
Immediate PTT, 1:1 Mix
0 – 99 Years:
< 30.9 sec
Incubated PTT, 1:1 Mix
0 – 99 Years:
< 33.6 sec
Thrombin Time
0 – 1 Days:
< 17.4 sec
2 – 5 Days:
< 17.9 sec
6 – 30 Days:
< 17.9 sec
1 – 3 Months:
< 18.2 sec
4 – 11 Months:
< 19.1 sec
1 – 99 Years:
< 18.6 sec
Heparin Anti Xa
0 – 99 Years:
Therapeutic range: 0.3 – 0.7 (standard nomogram) IU/mL
0 – 99 Years:
< 0.10 IU/mL
0 – 99 Years:
Stroke or low dose protocol: 0.2 – 0.5 IU/mL