II. Background

  1. Evaluates the Extrinsic Clotting Pathway
  2. Plasma collected in a tube containing citrate, which binds Calcium and prevents initial clotting
  3. Both Calcium and Tissue Thromboplastin added to plasma
  4. Tissue Thromboplastin activates the Extrinsic Clotting Pathway which is fast (compared with Intrinsic Clotting Pathway)

III. Precautions

  1. International Normalized Ratio (INR) and ProTime (PT) were developed only to monitor Warfarin
    1. Cirrhosis may be associated with an increased INR/PT, but may also be Hypercoagulable

IV. Labs: Normal

  1. International Normalized Ratio (INR)
    1. See Warfarin
  2. ProTime (replaced by INR)
    1. Range: 10-12 sec (11-15 sec in some assays)

V. Causes: Increased

VI. Causes: Decreased

  1. Vitamin K supplementation
  2. Thrombophlebitis
  3. Medications
    1. Glutethimide
    2. Estrogens
    3. Griseofulvin
    4. Diphenhydramine

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Related Studies

Ontology: Prothrombin time assay (C0033707)

Definition (MSHCZE) Quickův test (protrombinový čas, zkr. PT, QT) – test k vyšetření koagulace krve. Provádí se s dekalcifikovanou plasmou (z krve odebrané do citrátu). Testuje tzv. zevní systém aktivace (systém tkáňového faktoru). K plasmě se přidává tkáňový faktor (tromboplastin, faktor III) a koagulace se spouští kalciem. Měří se doba, za kterou dojde ke koagulaci. K ní dojde v normální krvi cca za 12–15 sekund, výsledek se pak vyjadřuje jako tzv. INR. Q. t. slouží jako základní koagulační test, užívá se k monitorování antikoagulační terapie warfarinem či dikumaroly (antagonisty vitaminu K), k vyšetření funkcí jater (schopnost proteosyntézy). Prodloužen je např. při jaterní cirhóze, déle trvajícím obstrukčním ikteru( malabsorpce vitaminu K), antikoagulační terapii. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ )
Definition (NCI_CDISC) A blood clotting measurement that evaluates the extrinsic pathway of coagulation.
Definition (NCI) A measurement of the clotting time of plasma recalcified in the presence of excess tissue thromboplastin; it is a measure of the extrinsic pathway of coagulation. It is used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage and vitamin K status. Factors measured are fibrinogen, prothrombin, and factors V, VII, and X.
Definition (MSH) Clotting time of PLASMA recalcified in the presence of excess TISSUE THROMBOPLASTIN. Factors measured are FIBRINOGEN; PROTHROMBIN; FACTOR V; FACTOR VII; and FACTOR X. It is used for monitoring anticoagulant therapy with COUMARINS.
Definition (CSP) clotting time of plasma recalcified in the presence of excess tissue thromboplastin; used for monitoring anticoagulant therapy with coumarins.
Concepts Laboratory Procedure (T059)
MSH D011517
SnomedCT 90735005, 142979005, 396451008
CPT 85610, 1014271
English Prothrombin Time, Prothrombin Times, Time, Prothrombin, Times, Prothrombin, One stage prothrombin time, PROTHROMBIN TIME, Prothrombin time (PT), Prothrombin test, Prothrombin Time Test, PTT - Prothrombin time, prothrombin time (PT) (lab test), prothrombin time (PT), prothrombin time, Pro-thrombin time, prothrombin times, Test;prothrombin time, Prothrombin time assay, prothrombin test, prothrombin time (PT) test, Prothrombin time test, One stage prothrombin time (procedure), PT, Plasma Prothrombin Test, Protime, Quick one stage prothrombin time, Prothrombin time, PT assay, PT - Prothrombin time, Prothrombin time (procedure), prothrombin time test
Dutch protrombinetest, protrombinetijdtest, protrombinetijd, Protrombinetijd
French Test de temps de prothrombine, Test de prothrombine, Temps de prothrombine, TT (Temps de Prothrombine), TP
German Prothrombinzeittest, Prothrombintest, Prothrombinzeit
Italian Analisi della protrombina, Analisi del tempo di protrombina, Tempo di protrombina
Portuguese Exame de tempo de protrombina, Prova de protrombina, Tempo de protrombina, Tempo de Protrombina
Spanish Prueba de tiempo de protrombina, Prueba de protrombina, tiempo de protrombina rápido en un paso, tiempo de PT, tiempo de protrombina (procedimiento), tiempo de protrombina, Tiempo de protrombina, Tiempo de Protrombina
Japanese プロトロンビン試験, プロトロンビン時間試験, プロトロンビンジカン, プロトロンビンジカンシケン, プロトロンビンシケン, ラッセルクサリヘビ毒時間, トロンボ試験, トロンボテスト, クイックテスト, プロトロンビン時間
Swedish Protrombintid
Finnish Protrombiiniaika
Russian PROTROMBINOVOE VREMIA, RASSELA ZMEINYI IAD, VREMIA, TROMBOTEST, ПРОТРОМБИНОВОЕ ВРЕМЯ, РАССЕЛА ЗМЕИНЫЙ ЯД, ВРЕМЯ, ТРОМБОТЕСТ
Czech Protrombinový test, Protrombinový čas, protrombinový čas, PT, prothrombinový čas
Polish Czas Quicka, Czas protrombinowy
Hungarian Prothrombin idő vizsgálat, Prothrombin idő, Prothrombin vizsgálat
Norwegian Protrombintid

Ontology: International Normalized Ratio (C0525032)

Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (CHV) a unit used to report blood coagulation test
Definition (NCI) A system, commonly called the INR, established by the World Health Organization (WHO) and the International Committee on Thrombosis and Hemostasis for reporting the results of blood coagulation (clotting) tests. All results are standardized using the international sensitivity index (ISI) for the particular thromboplastin reagent and instrument combination utilized to perform the test; the ratio of a patient's clotting time to the lab's mean reference value is normalized against the ISI. (from medterms.com and medicine.ucsf.edu)
Definition (NCI_CDISC) A ratio that represents the prothrombin time for a plasma specimen, divided by the result for a control plasma specimen, further standardized for the International Sensitivity Index of the tissue factor (thromboplastin) used in the test.
Definition (NCI) A measure of the extrinsic pathway of coagulation. The International Normalized Ratio of Prothrombin Time (INR) is the ratio of a patient prothrombin time to a normal (control) sample raised to the power of the International Sensitivity Index (ISI) with a range of 0.8 to 1.2 seconds.
Definition (MSH) System established by the World Health Organization and the International Committee on Thrombosis and Hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the International Sensitivity Index for the particular test reagent/instrument combination used.
Concepts Laboratory Procedure (T059)
MSH D019934
SnomedCT 142988001, 165581004
LNC LP20762-8
English INR, INR - Internationalized ratio, International Normalized Ratios, Internationalized ratio, Normalized Ratio, International, Normalized Ratios, International, Ratio, International Normalized, Ratios, International Normalized, International Normalized Ratio of Prothrombin Time, international normalized ratio (INR), international normalized ratio (INR) (lab test), BCR, coagulation studies: INR, bcr, international normalising ratio, international normalize ratio, international normalized ratio, international normalised ratio, international normalizing ratio, international normalized ratios, internationalised ratio, International normalised ratio (procedure), Prothrombin Intl. Normalized Ratio, INR - Internationalised ratio, Internationalised ratio, International normalised ratio, International normalized ratio, International normalized ratio (observable entity), International Normalized Ratio
Italian Rapporto internazionale normalizzato, INR, BCR (INR), International Normalized Ratio
Dutch BCR, internationale genormaliseerde ratio, INR, Ratio, internationale genormaliseerde
French BCR, Rapport normalisé international, RIN, INR (International Normalized Ratio), TNI (Taux Normalisé International), INR, Taux normalisé international
German BCR, International normalized ratio, International normalised ratio, INR, International Normalized Ratio
Portuguese Relação internacional normalizada, BCR, International Normalized Ratio, Relação normalizada internacional, INR, Coeficiente Internacional Normatizado
Spanish INR, Razón normalizada internacional, RIN, razón internacional normatizada (entidad observable), razón internacional normatizada, Proporción normalizada internacional, RNI, Relación Normalizada Internacional
Japanese BCR, BCR, 国際正規化比, 国際標準化比, コクサイヒョウジュンヒ, INR, INR, 国際標準比
Swedish INR
Czech mezinárodní normalizační poměr, INR, Mezinárodně normalizovaný poměr, Mezinárodně normalizovaný poměr (international normalized ratio) INR
Finnish INR
Russian SVERTYVANIIA KROVI TESTOV MEZHDUNARODNAIA SISTEMA, СВЕРТЫВАНИЯ КРОВИ ТЕСТОВ МЕЖДУНАРОДНАЯ СИСТЕМА
Polish Wskaźnik INR, Współczynnik INR, INR
Hungarian INR, International normalised ratio (INR), BCR, Nemzetközi normalizált arány (INR)
Norwegian INR-verdier, INR, Internasjonalt normalisert forholdstall

Ontology: Point in time (C1442880)

Concepts Temporal Concept (T079)
LNC LP6960-1
English Pt, Point in time