Increased PTT Only: A Prolonged PTT with a Normal PT
Heparin in the specimen, which may be a result of heparin treatment of the patient
Treatment with low molecular weight heparin, argatroban, or lepirudin
A lupus anticoagulant (i.e., lupus inhibitor)
Deficiency of factor VIII (hemophilia A) or IX (hemophilia B)
Deficiency of factor VIII (mild or severe) associated with von Willebrand's disease
Deficiency of factor XI, XII, or prekallikrein (Fletcher factor)
An inhibitor to factor VIII or IX
Suggested Additional Lab Testing
If heparin contamination in the sample is a possibility, ask for a repeat PTT or, if necessary, get a heparin measurement.
To help differentiate between coagulation inhibitors and factor deficiencies, perform PTT mixing studies (patient plasma plus normal plasma in equal volumes).
A patient positive for the lupus anticoagulant should have at least one positive lupus anticoagulant screening test and at least one positive confirmatory test that involves detection of phospholipid neutralization by the lupus anticoagulant.
Factor assays for factors VIII, IX, XI XII, and, in rare circumstances, an assay for prekallikrein (Fletcher factor) can determine if a deficiency in one or more of these factors explains the prolonged PTT.
Bethesda Unit assay is used to quantitate the amount of antibody to factor VIII in a patient with a PTT mixing study result suggestive of a factor VIII inhibitor. An evaluation for von Willebrand includes factor VIII, von Willebrand factor, and ristocetin cofactor. The factor VIII in von Willebrand patients may not be low enough to prolong the PTT.
Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.
Sign Up for Free e-newsletters
- Chemotherapy-Related Fatigue Linked to Levothyroxine Use in Breast Cancer
- New Hypertension Threshold Guides Blood Pressure Management During Cancer Treatment
- Sexual Aids and Resources Not Readily Available at Cancer Centers
- Gas Mixture Improves Efficacy of Breakthrough Cancer Pain Treatment
- Factors Affecting Employment Participation in Early-stage Breast Cancer
- Sitting With Silence in End-of-Life Cancer Care
- Obesity and Cancer Risk (Fact Sheet)
- Susceptibility Gene Mutations Common in Those With Pancreatic Cancer and History of Other Cancers
- Anticancer Properties of Omega-3 Fatty Acids: Plant-Based vs Marine-Based
- US Pharmacopeia Revises Chapter on Handling Hazardous Drugs
- Exercise Before Lung Cancer Surgery Greatly Reduces Complications
- Hodgkin Lymphoma Treatment in EU vs US: Similarities Would Enable Worldwide Studies
- Zinc Sulfate Improves Chemotherapy-Induced Mucositis Outcomes in Leukemia
- 5-Year Overall Survival in Endometrial Cancer Not Improved With Chemoradiotherapy
- Travel Distance to Prostate Cancer Treatment Influences Treatment Choice
Regimen and Drug Listings
GET FULL LISTINGS OF TREATMENT Regimens and Drug INFORMATION
|Head and Neck Cancer||Regimens||Drugs|