# Thrombophilia (Clotting Tendency) - Category: chronic - Review status: reviewed (every claim checked against a document named on this page) - Sources: Hypercoagulability - StatPearls - NCBI Bookshelf - https://www.ncbi.nlm.nih.gov/books/NBK538251/ · ICPC-3 (WONCA International Classification of Primary Care, 3rd edition) class BD78.03 - condition scope only, no dose · No dose - referral pathway, no medicine given in primary care - Verified date: 2026-08 ## Verified against - No dose - referral pathway, no medicine given in primary care - Thrombophilia (Clotting Tendency) - disease-level clinical article (thrombophilia-clinical.txt) ## Treatment metadata - No drug therapy in primary care (Referral & Advice) ## Complete treatment card ```text THROMBOPHILIA (CLOTTING TENDENCY) Sources: Hypercoagulability - StatPearls - NCBI Bookshelf - https://www.ncbi.nlm.nih.gov/books/NBK538251/ · ICPC-3 (WONCA International Classification of Primary Care, 3rd edition) class BD78.03 - condition scope only, no dose · No dose - referral pathway, no medicine given in primary care Review status: REVIEWED against No dose - referral pathway, no medicine given in primary care, Thrombophilia (Clotting Tendency) - disease-level clinical article (thrombophilia-clinical.txt) (2026-08) IS IT THIS? - reference only, to read alongside your own examination SYMPTOMS - what the patient reports (4) - When clots occur, they most often affect the deep leg veins or lungs, though superficial leg veins or the cerebral, portal, or hepatic veins can also be affected - An isolated pulmonary embolism without any leg clot can occur but is actually less common in factor V Leiden carriers than in the general population, a pattern called the factor V Leiden paradox - Cerebral vein clots are a risk, particularly with oral contraceptive use, and factor V Leiden has also been linked to a higher risk of Budd-Chiari syndrome - Stroke risk is modestly increased, particularly in women, smokers, and younger patients TESTS (12) - ASH guidelines discourage thrombophilia testing after a first DVT or PE, since it is costly without clear clinical benefit - Testing is considered for VTE occurring before age 50 - Testing is also considered for clots in unusual sites such as the ovarian, portal, or renal veins - An unexplained arterial clot is another reason to test for thrombophilia - A strong family history of thrombophilia also prompts testing - A hospitalized patient who clots despite preventive anticoagulation, with no other explanation, is a testing candidate - Unexplained recurrent DVT or PE is also an indication for testing - Testing is generally skipped after a first, provoked clot or one occurring after age 50 - Diagnosis uses either genetic mutation analysis or a functional APC resistance coagulation test - A positive functional APC resistance test should be confirmed with genetic testing - PCR-based mutation testing works because a restriction enzyme cuts normal DNA but not the mutated gene, producing a distinct gel banding pattern - The functional APC resistance assay is cheaper but can give a falsely normal result in patients on direct thrombin or factor Xa inhibitors, or with a lupus anticoagulant IF NOT THIS - what else fits (12) - Prothrombin G20210A mutation - Protein S deficiency - Protein C deficiency - Antithrombin (AT) deficiency - Malignancy - Pregnancy or use of oral contraceptives - Immobilization/obesity - Nephrotic syndrome - Antiphospholipid syndrome - Paroxysmal nocturnal hemoglobinuria - Myeloproliferative disorders - Medications like tamoxifen, thalidomide, or lenalidomide Source StatPearls "Factor V Leiden Mutation" - disease-level clinical article Status traced to the source above 1. NO DRUG THERAPY IN PRIMARY CARE (REFERRAL & ADVICE) [1st line] Adult Inherited or acquired tendency to abnormal blood clotting. Diagnosis requires specialist coagulation work-up; GP gives urgent advice and initial anticoagulation if a clot is suspected, and may continue long-term anticoagulation once a specialist has set the plan. - Refer, with advice Peds Children follow the same pathway: recognise and refer. No primary-care medicine is implied. Source No dose - referral pathway, no medicine given in primary care Why Inherited or acquired tendency to abnormal blood clotting. Diagnosis requires specialist coagulation work-up; GP gives urgent advice and initial anticoagulation if a clot is suspected, and may continue long-term anticoagulation once a specialist has set the plan. Caution No medicine is prescribed for this in primary care - this entry is for recognition and referral. Anything given is decided by the service it is referred to. RED FLAG - Indefinite anticoagulation is strongly recommended for unprovoked, life- threatening VTE, recurrent VTE, or VTE at unusual locations. RED FLAG - Homozygous thrombophilia patients undergoing surgery require prophylactic anticoagulation as a high-risk population. RED FLAG - Unilateral leg swelling or pain (possible DVT), or sudden breathlessness or chest pain (possible PE). Features that should prompt referral include recurrent pregnancy loss and a clot at a young age or without an obvious trigger. Prices are indicative (dataset snapshot 2026-06); verify with the pharmacy. ``` --- Dawaa Reference is a reference for prescribers, not a medical device, and does not replace clinical judgement. [Privacy policy](/privacy)