Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1183 page)

   Prothrombin c.20210G>A testing may be considered in the following cases:

   Women with unexplained early-onset severe preeclampsia, placental abruption, or significant intrauterine growth retardation

   A first VTE related to tamoxifen or other selective estrogen receptor modulators (SERM)

   Female smokers younger than 50 years with a myocardial infarction

   Individuals older than age 50 years with a first provoked VTE in the absence of malignancy or an intravascular device

   Asymptomatic adult family members of probands with one or two known c.20210G>A mutation in the F2 gene, especially those with a strong family history of VTE at a young age

   Asymptomatic female family members of probands with known prothrombin thrombophilia who are pregnant or who are considering oral contraception or pregnancy

   Women with recurrent unexplained first-trimester loss with or without second- or third-trimester loss

   Children with arterial thrombosis

   Limitations

   The results of a genetic test may be affected by DNA rearrangements, blood transfusion, bone marrow transplantation, or rare sequence variations.

   Genetic causes of thrombosis, other than the prothrombin c.20210G>A mutation, will not be detected.

PROTHROMBIN TIME (PT) AND THE INTERNATIONAL NORMALIZED RATIO (INR)
*

   Definition