thrombophilia

DEFINITION of thrombophilia

Thrombophilia is a clinical condition defined by a hereditary or acquired predisposition to pathological thrombosis, arising from defects or deficiencies in the coagulation cascade, natural anticoagulant proteins, or fibrinolytic system that tip the hemostatic balance toward excessive or spontaneous clot formation.^[1] It is distinguished from normal hemostasis — the physiological clotting response to vascular injury — in that thrombophilia produces thrombus formation in the absence of an appropriate provoking stimulus, or an exaggerated clotting response disproportionate to the trigger. The underlying mechanisms include gain-of-function mutations that amplify procoagulant activity (e.g., Factor V Leiden, prothrombin G20210A mutation), loss-of-function deficiencies in natural anticoagulants (protein C, protein S, antithrombin III), or acquired immune-mediated disruption of phospholipid-binding proteins as seen in antiphospholipid syndrome.^[2] Thrombophilia is pathological by definition, though its clinical severity ranges from an asymptomatic incidental laboratory finding to recurrent, life-threatening venous thromboembolism (VTE); it has no physiological counterpart in healthy individuals. Clinically relevant coded subtypes include activated protein C resistance/Factor V Leiden (D68.51), prothrombin gene mutation (D68.52), other primary thrombophilias encompassing protein C/S and antithrombin III deficiency (D68.59), antiphospholipid syndrome (D68.61), and lupus anticoagulant syndrome (D68.62).^[3] thrombophilia is commonly confused with coagulopathy, which broadly encompasses any disorder of coagulation — including hemorrhagic disorders — whereas thrombophilia specifically and exclusively denotes a prothrombotic, clot-promoting tendency.

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ETYMOLOGY of thrombophilia

greek

Component	Origin	Meaning
thrombo-	Greek thrombos (THROM-bos)	“clot,” “lump,” “curd” — combining form denoting a blood clot or coagulum; relational combining form linking terms to coagulation processes
-philia	Greek philia (fee-LEE-ah), from philos (FEE-los)	Noun-forming suffix — “love of,” “affinity for,” “tendency toward” — used in medicine to denote an abnormal attraction or pathological predisposition

The word entered English in the 1960s as thrombophilia (noun), a modern medical coinage formed directly from Greek thrombos (“clot, curd”) and philia (“love, affinity, tendency”); the term emerged in hematology literature alongside the first descriptions of hereditary antithrombin III deficiency. The root thrombo- (“clot”) connects thrombophilia to the entire -thrombo- root family: thrombosis (thrombo- + -osis → “condition of clotting”), thrombocyte (thrombo- + -cyte → “clotting cell; platelet”), thromboembolism (thrombo- + embol- + -ism → “dislodged clot traveling through vasculature”), and thrombolysis (thrombo- + -lysis → “enzymatic breakdown or dissolution of a clot”). The noun-forming suffix -philia (“tendency toward”) is shared with hemophilia (hemo- + -philia → “affinity for bleeding; hereditary bleeding disorder”), eosinophilia (eosinophil + -ia → “pathological excess of eosinophils”), and basophilia (basophil + -ia → “excess of basophils or increased basophilic staining”).

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🔀 ALIASES / ALTERNATE TERMS

• Thrombophilic (adjective form — used in clinical collocations including “thrombophilic state,” “thrombophilic mutation,” “thrombophilic workup,” and “thrombophilic patient”)
• Hypercoagulable state (most common clinical synonym; used interchangeably across hematology, hospitalist, surgical, and critical care settings; coded under D68.51–D68.69 depending on documented etiology)
• Hypercoagulability (abstract noun form describing the physiological property of excess clot-promoting activity; used in laboratory and research contexts)
• Prothrombotic state (clinical descriptor emphasizing the mechanistic risk environment rather than a named diagnosis; used in cardiology and hematology literature)
• Thrombotic diathesis (formal clinical synonym denoting a constitutional predisposition to thrombosis; diathesis = inherent susceptibility; used in hematology and rheumatology literature)
• Primary thrombophilia (inherited/genetic form — encompasses Factor V Leiden, prothrombin gene mutation, protein C deficiency, protein S deficiency, and antithrombin III deficiency; coded D68.51–D68.59)
• Secondary thrombophilia (acquired form — encompasses antiphospholipid syndrome, malignancy-associated hypercoagulability, and pregnancy-related prothrombotic states; coded D68.61–D68.69)
• Antiphospholipid syndrome (APS) (immune-mediated acquired thrombophilia characterized by persistent antiphospholipid antibodies causing both venous and arterial thrombosis plus pregnancy morbidity; D68.61)
• Lupus anticoagulant syndrome (subset of the antiphospholipid antibody spectrum defined by presence of lupus anticoagulant antibody; paradoxically prolongs aPTT in vitro yet causes thrombosis in vivo; D68.62)
• Activated protein C resistance (APCR) (laboratory phenotype most commonly caused by Factor V Leiden mutation; the most prevalent inherited thrombophilia; D68.51)
• Factor V Leiden (the specific point mutation [R506Q] in the Factor V gene underlying APCR; clinical documentation of “Factor V Leiden” maps to D68.51 — not a separate ICD-10-CM code)
• Prothrombin gene mutation (G20210A / Factor II mutation) (second most common inherited thrombophilia; gain-of-function mutation increasing circulating prothrombin levels; D68.52)

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🔗 RELATED TERMS

• Thrombosis — the pathological end result of unchecked thrombophilia; formation of a blood clot (thrombus) within a blood vessel causing partial or complete occlusion; can affect veins (DVT, PE) or arteries (stroke, MI)
• Hemophilia — the clinical antithesis of thrombophilia; shares the -philia suffix but denotes a hereditary bleeding disorder caused by deficiency of clotting factors VIII (hemophilia A) or IX (hemophilia B), producing impaired coagulation rather than excess
• Coagulopathy — a broad umbrella term encompassing any disorder of the coagulation system, including both hemorrhagic and prothrombotic conditions; thrombophilia is a prothrombotic subset of coagulopathy
• Venous thromboembolism (VTE) — the most common and clinically significant complication of thrombophilia, encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE); principal inpatient diagnoses coded under I82.x and I26.x respectively
• Deep vein thrombosis]] (DVT) — thrombosis within the deep venous system, most commonly the lower extremity iliofemoral or popliteal veins; the most frequent acute presentation triggering a thrombophilia workup
• Pulmonary embolism (PE) — potentially fatal complication of DVT in which the thrombus dislodges and occludes the pulmonary vasculature; coded I26.01–I26.99 depending on hemodynamic severity and saddle vs. subsegmental distribution
• Protein C deficiency — hereditary loss-of-function deficiency in the natural anticoagulant protein C, which normally inactivates coagulation factors Va and VIIIa; results in a prothrombotic state; coded under D68.59
• Protein S deficiency — hereditary deficiency in protein S, an essential cofactor for activated protein C; impairs the anticoagulant pathway and predisposes to VTE; coded under D68.59
• Antithrombin III (AT-III) deficiency — inherited or acquired deficiency of antithrombin III, the primary serine protease inhibitor of thrombin and factor Xa; associated with high absolute thrombotic risk; coded under D68.59
• Antiphospholipid syndrome (APS) — acquired immune-mediated thrombophilia defined by persistent antiphospholipid antibodies (anticardiolipin IgG/IgM, beta-2 glycoprotein I, lupus anticoagulant); causes both venous and arterial thrombosis plus pregnancy morbidity; D68.61^[4]
• Anticoagulation — the cornerstone therapeutic intervention for thrombophilia-related thrombosis and prophylaxis in high-risk settings; encompasses unfractionated heparin, low-molecular-weight heparin, warfarin, and direct oral anticoagulants (DOACs)
• Fibrinolysis — the physiological process of clot breakdown and dissolution; defective fibrinolysis contributes to the thrombophilic state in certain acquired conditions and hypofibrinolytic syndromes
• Hypercoagulability workup — the systematic laboratory evaluation performed to identify the etiology of thrombophilia; includes genetic, functional coagulation, and immunological assay panels

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CODING CORNER

🏥 ICD-10-CM CODES

Primary Thrombophilia | Inherited / Genetic Forms

Code	Description
D68.51	Activated protein C resistance (Factor V Leiden mutation)
D68.52	Prothrombin gene mutation (Factor II G20210A)
D68.59	Other primary thrombophilia (includes protein C deficiency, protein S deficiency, antithrombin III deficiency, NOS)

Other Thrombophilia | Acquired / Immune-Mediated Forms

Code	Description
D68.61	Antiphospholipid syndrome (APS)
D68.62	Lupus anticoagulant syndrome
D68.69	Other thrombophilia NEC

Personal and Family History | Status Codes

Code	Description
Z86.718	Personal history of other venous thrombosis and thromboembolism (use when prior thrombophilia-related VTE episode is resolved)
Z84.81	Family history of carrier of genetic disease (use for family history of inherited thrombophilia when patient has not yet been tested)

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🔧 COMMON CPT CODES (Thrombophilia-Related Diagnosis & Workup)

CPT Code	Description
85307	Activated protein C (APC) resistance assay — primary functional screening test for Factor V Leiden / D68.51
81241	F5 gene analysis — Factor V Leiden variant; confirmatory molecular genetic test for activated protein C resistance
81240	F2 gene analysis — prothrombin G20210A variant; confirmatory molecular genetic test for prothrombin gene mutation / D68.52
85300	Antithrombin III (AT-III) activity assay (functional clot-based assay)
85301	Antithrombin III (AT-III) antigen assay (immunologic quantification)
85302	Protein C antigen assay (immunologic quantification)
85303	Protein C activity assay (clot-based or chromogenic functional assay)
85305	Protein S total antigen assay
85306	Protein S free antigen assay (free fraction most clinically relevant for thrombotic risk)
85613	Russell viper venom time, diluted (DRVVT) — primary screening test for lupus anticoagulant / D68.62
86147	Cardiolipin (phospholipid) antibody — anticardiolipin IgG or IgM (APS workup / D68.61)
86146	Beta-2 glycoprotein I antibody — each Ig class (APS confirmatory workup / D68.61)
85730	Thromboplastin time, partial (aPTT); plasma — baseline coagulation screening and anticoagulation monitoring
85610	Prothrombin time (PT/INR) — baseline coagulation screening and warfarin anticoagulation monitoring

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⚠️ Coding Note: Thrombophilia codes (D68.51–D68.69) are sequenced as additional diagnoses on inpatient claims — when a thromboembolic event (DVT, PE) is the reason for admission, the VTE code is the principal diagnosis with the thrombophilia coded secondarily to capture the underlying etiology and support clinical complexity. Factor V Leiden is a high-yield undercoding trap: physicians frequently document “Factor V Leiden,” “APC resistance,” or “activated protein C resistance” without connecting it to D68.51, and coders should recognize all three phrasings as mapping to the same code — a CDI query should prompt the attending to confirm and document the relationship. D68.61 (antiphospholipid syndrome) requires a confirmed physician diagnosis of APS; a positive antiphospholipid antibody result alone does not support this code, and a CDI query is appropriate when lab findings are present but APS is not explicitly documented. D68.62 (lupus anticoagulant syndrome) is clinically and administratively distinct from systemic lupus erythematosus (M32.x) — lupus anticoagulant frequently occurs without an underlying SLE diagnosis, and the two should never be assumed to co-exist without specific physician documentation. When thrombophilia is identified for the first time during an inpatient admission (e.g., during VTE workup), both the current thromboembolic event and the newly diagnosed thrombophilia should be reported as additional diagnoses; use Z86.718 only when the prior VTE episode has fully resolved and only its history is relevant to the current stay.

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DERIVATIONS of thrombophilia

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(roots, (word) => econtains([[thrombophilia]].roots, word))) > 0 AND file.name != [[thrombophilia]].file.name
SORT file.name ASC

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Query functionality

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(definition, (word) => econtains([[thrombophilia]].definition, word))) > 0 AND file.name != [[thrombophilia]].file.name

Med roots dictionary Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms