antithrombin 3 in plasma (antithrombin 3 assay)

Introduction

Reference range:

• adults: 19-30 mg/dL (antigenic assay)
• 80-120% (functional assay)

Clinical significance

• used to evaluate hypercoagulable states
• used to identify cause of heparin resistance
• deficiency in antithrombin-3 increases the tendency towards coagulation (hypercoagulable state)

Increases

• inflammation
• menstruation
• renal transplantation
• acute hepatitis
• obstructive jaundice
• vitamin K deficiency
• pharmaceutical agents
  • anabolic steroids, androgens
  • oral contraceptives containing progesterone
  • warfarin
  • gemfibrozil

Decreases

• hereditary familial antithrombin-3 deficiency
• disseminated intravascular coagulation (DIC)
• hypercoagulable states (deep vein thrombosis)
• hepatic cirrhosis
• nephrotic syndrome
• protein-losing enteropathy
  • protein wasting of malignancy
• liver transplantation
• partial hepatectomy
• pharmaceutical agents
  • fibrinolytics
  • heparin
  • L-asparaginase
  • oral contraceptives containing estrogen

Methods

• antigenic assay: fixed rate time nephelometry
• functional assay: coagulation testing, chromogenic substrate (spectrophotometry)

Specimen

• plasma, sodium citrate (light blue-top).
• minimal volume 0.5 mL.

• antigenic assay
  • do not thaw & refreeze
  • patient should abstain from anabolic steroids, gemfibrozil, warfarin, heparin, asparaginase, estrogens, gestodene & oral contraceptives for 3 days prior to specimen collection
  • shipping: refrigerated, frozen
  • stability:
  • room temp = 6 hours
  • refrigerated = 3 days
  • frozen = 3 weeks
• functional assay:
  • shipping: frozen (do not thaw)

More general terms

• special chemistry test

More specific terms

• antithrombin 3 antigen in plasma
• antithrombin 3 in activity

Additional terms

• antithrombin-III (ATIII, heparin cofactor, SERPINC1, AT3, PRO0309)

Patient information

antithrombin 3 assay patient information