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Heparin Laboratory/Dosing Algorithm post-initial bolus therapy

Item Value
Available Stat? No
Test code
Test group Heparin
Container type
Sample type
Normal range
Synonyms Monitoring Anticoagulation; UFH ; LMWH; Enoxaparin; Unfractionated heparin; Low molecular weight heparin
Additional information Recommendations regarding anticoagulation and monitoring of anticoagulation can be obtained from the Hematology Consultation service, which can be contacted at pager 443-4276.

Refer to "Intravenous Heparin Order Form (Adults)" or "Antithrombotic therapy Order Form (Adults) Cardiology Service Only" for more complete information. The information below is for reference purposes only.

Adult patients receiving > 35,000 units/day of unfractionated heparin may benefit from monitoring with Heparin Levels. Ref: Arch Intern Med 1994 154:49-56.

Heparin Laboratory/Dosing Algorithm post-initial bolus therapy:

1. Obtain first PTT 6 hours after initiation of heparin therapy.


3. Obtain PTTs Q6 hours until therapeutic or after a dose change and adjust rate using TABLE below*

4. Obtain daily PTT after PTT is stable*

5. Obtain daily CBC & platelets

6. Obtain stool guaiac every other day

PTT Re-Bolus Hold Drip (min) Change drip (U/hour) Repeat PTT in
< 40 If indicated 0 +200 6 hours
40-45.9 0 0 +200 6 hours
46-52.9 0 0 +100 6 hours
53-74.9 (Therapeutic Range) 0 0 0 Q6 until stable* then QAM
75-85.9 0 0 -100 6 hours
86-94.9 0 30 min. -200 6 hours
≥ 95 0 60 min. -300 6 hours

*Stable=2 consecutive aPTT values within therapeutic range [aPTT 53-74.9]

Note: This chart is designed for use only at Moffitt/Long/Mt Zion Hospitals. Because the PTT therapeutic range MAY DIFFER between Moffitt/Long/Mt Zion and other hospital laboratories it cannot be assumed to be appropriate for use elsewhere.
Last Updated 10/11/2012 11:02:52 AM
Entry Number 470
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