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Clinical use of coagulation tests

James L Zehnder, MD
Section Editor
Lawrence LK Leung, MD
Deputy Editor
Jennifer S Tirnauer, MD


Several tests of the coagulation system are available, including the prothrombin time (PT), activated partial thromboplastin time (aPTT), and others; these may be ordered in a variety of clinical settings. This topic reviews the principles and interpretation of coagulation tests that are routinely available for clinical use.

Additional information regarding the use of these tests in specific clinical settings is presented separately:

Unexplained bleeding – (see "Approach to the adult patient with a bleeding diathesis" and "Approach to the child with bleeding symptoms")

Preoperative testing – (see "Preoperative assessment of hemostasis")

Monitoring anticoagulation:

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Literature review current through: Nov 2017. | This topic last updated: Nov 02, 2017.
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  1. Adcock DM, Kressin DC, Marlar RA. Minimum specimen volume requirements for routine coagulation testing: dependence on citrate concentration. Am J Clin Pathol 1998; 109:595.
  2. Chuang J, Sadler MA, Witt DM. Impact of evacuated collection tube fill volume and mixing on routine coagulation testing using 2.5-ml (pediatric) tubes. Chest 2004; 126:1262.
  3. Zürcher M, Sulzer I, Barizzi G, et al. Stability of coagulation assays performed in plasma from citrated whole blood transported at ambient temperature. Thromb Haemost 2008; 99:416.
  4. Gottfried EL, Adachi MM. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. Am J Clin Pathol 1997; 107:681.
  5. Brigden ML, Graydon C, McLeod B, Lesperance M. Prothrombin time determination. The lack of need for a discard tube and 24-hour stability. Am J Clin Pathol 1997; 108:422.
  6. McLaren G, Hanna C, Mills L, et al. Comparison of sampling methods for obtaining accurate coagulation values in hemodialysis patients with heparinized central venous catheters. Nephrol Nurs J 2001; 28:632.
  7. Besley M, Thomas A, Salter S, et al. Control of oral anticoagulation in patients using long-term internal jugular catheters for haemodialysis access. Int J Artif Organs 1992; 15:277.
  8. van Genderen PJ, Gomes M, Stibbe J. The reliability of Hickman catheter blood for the assessment of activation markers of coagulation and fibrinolysis in patients with hematological malignancies. Thromb Res 1994; 73:247.
  9. Delate T, Witt DM, Jones JR, et al. Falsely elevated international normalized ratio values in patients undergoing anticoagulation therapy: a descriptive evaluation. Chest 2007; 131:816.
  10. Spaet TH. Case 20-1979: false prolongation of prothrombin time in polycythemia. N Engl J Med 1979; 301:503.
  11. Hirsh J, Poller L. The international normalized ratio. A guide to understanding and correcting its problems. Arch Intern Med 1994; 154:282.
  12. Becker DM, Humphries JE, Walker FB 4th, et al. Standardizing the prothrombin time. Calibrating coagulation instruments as well as thromboplastin. Arch Pathol Lab Med 1993; 117:602.
  13. van den Besselaar AM, Poller L, Tripodi A. Guidelines for thromboplastins and plasmas used to control oral anticoagulant therapy. WHO Technical Report Series 1999; 889:64.
  14. Funk DM. Coagulation assays and anticoagulant monitoring. Hematology Am Soc Hematol Educ Program 2012; 2012:460.
  15. Jin J, Zehnder JL. Prozone Effect in the Diagnosis of Lupus Anticoagulant for the Lupus Anticoagulant-Hypoprothrombinemia Syndrome. Am J Clin Pathol 2016; 146:262.
  16. Schmaier AH. Contact activation: a revision. Thromb Haemost 1997; 78:101.
  17. Price EA, Jin J, Nguyen HM, et al. Discordant aPTT and anti-Xa values and outcomes in hospitalized patients treated with intravenous unfractionated heparin. Ann Pharmacother 2013; 47:151.
  18. Malbora B, Bilaloglu E. Lupus Anticoagulant Positivity in Pediatric Patients With Prolonged Activated Partial Thromboplastin Time: A Single-Center Experience and Review of Literature. Pediatr Hematol Oncol 2015; 32:495.
  19. JIM RT. A study of the plasma thrombin time. J Lab Clin Med 1957; 50:45.
  20. Mammen EF. Seminars in Thrombosis and Hemostasis. Semin Thromb Hemost 1983; 9:1.
  21. Tripodi A, Mannucci PM. The coagulopathy of chronic liver disease. N Engl J Med 2011; 365:147.
  22. Toulon P, Frere E, Bachmeyer C, et al. Fibrin polymerization defect in HIV-infected patients--evidence for a critical role of albumin in the prolongation of thrombin and reptilase clotting times. Thromb Haemost 1995; 73:349.
  23. O'Kane MJ, Wisdom GB, Desai ZR, Archbold GP. Inhibition of fibrin monomer polymerisation by myeloma immunoglobulin. J Clin Pathol 1994; 47:266.
  24. Zehnder JL, Leung LL. Development of antibodies to thrombin and factor V with recurrent bleeding in a patient exposed to topical bovine thrombin. Blood 1990; 76:2011.
  25. Rapaport SI, Zivelin A, Minow RA, et al. Clinical significance of antibodies to bovine and human thrombin and factor V after surgical use of bovine thrombin. Am J Clin Pathol 1992; 97:84.
  26. Niewiarowski S, Kirby EP, Stocker K. Throbocytin-a novel platelet activating enzyme from Bothrops atrox venom. Thromb Res 1977; 10:863.
  27. Arnout J, Meijer P, Vermylen J. Lupus anticoagulant testing in Europe: an analysis of results from the first European Concerted Action on Thrombophilia (ECAT) survey using plasmas spiked with monoclonal antibodies against human beta2-glycoprotein I. Thromb Haemost 1999; 81:929.
  28. Potgieter JJ, Damgaard M, Hillarp A. One-stage vs. chromogenic assays in haemophilia A. Eur J Haematol 2015; 94 Suppl 77:38.
  29. Kitchen S, Kershaw G, Tiefenbacher S. Recombinant to modified factor VIII and factor IX - chromogenic and one-stage assays issues. Haemophilia 2016; 22 Suppl 5:72.
  30. Weitz JI, Fredenburgh JC, Eikelboom JW. A Test in Context: D-Dimer. J Am Coll Cardiol 2017; 70:2411.
  31. Perry DJ, Fitzmaurice DA, Kitchen S, et al. Point-of-care testing in haemostasis. Br J Haematol 2010; 150:501.
  32. Teien AN, Lie M. Evaluation of an amidolytic heparin assay method: increased sensitivity by adding purified antithrombin III. Thromb Res 1977; 10:399.
  33. Welsby IJ, McDonnell E, El-Moalem H, et al. Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass. J Clin Monit Comput 2002; 17:287.
  34. Furuhashi M, Ura N, Hasegawa K, et al. Sonoclot coagulation analysis: new bedside monitoring for determination of the appropriate heparin dose during haemodialysis. Nephrol Dial Transplant 2002; 17:1457.
  35. Hirsh J, Warkentin TE, Raschke R, et al. Heparin and low-molecular-weight heparin: mechanisms of action, pharmacokinetics, dosing considerations, monitoring, efficacy, and safety. Chest 1998; 114:489S.
  36. Nowak G. The ecarin clotting time, a universal method to quantify direct thrombin inhibitors. Pathophysiol Haemost Thromb 2003; 33:173.
  37. Gosselin RC, King JH, Janatpour KA, et al. Comparing direct thrombin inhibitors using aPTT, ecarin clotting times, and thrombin inhibitor management testing. Ann Pharmacother 2004; 38:1383.
  38. Fenyvesi T, Jörg I, Harenberg J. Monitoring of anticoagulant effects of direct thrombin inhibitors. Semin Thromb Hemost 2002; 28:361.
  39. Salmela B, Joutsi-Korhonen L, Saarela E, Lassila R. Comparison of monitoring methods for lepirudin: impact of warfarin and lupus anticoagulant. Thromb Res 2010; 125:538.
  40. Lossing TS, Kasper CK, Feinstein DI. Detection of factor VIII inhibitors with the partial thromboplastin time. Blood 1977; 49:793.
  41. el-Sayed MS. Effects of exercise on blood coagulation, fibrinolysis and platelet aggregation. Sports Med 1996; 22:282.
  42. Ogasawara M, Aoki K, Katano K, et al. Activated partial thromboplastin time is a predictive parameter for further miscarriages in cases of recurrent fetal loss. Fertil Steril 1998; 70:1081.
  43. Landi G, D'Angelo A, Boccardi E, et al. Venous thromboembolism in acute stroke. Prognostic importance of hypercoagulability. Arch Neurol 1992; 49:279.
  44. Reddy NM, Hall SW, MacKintosh FR. Partial thromboplastin time: prediction of adverse events and poor prognosis by low abnormal values. Arch Intern Med 1999; 159:2706.
  45. Tripodi A, Chantarangkul V, Martinelli I, et al. A shortened activated partial thromboplastin time is associated with the risk of venous thromboembolism. Blood 2004; 104:3631.
  46. Aboud MR, Ma DD. Increased incidence of venous thrombosis in patients with shortened activated partial thromboplastin times and low ratios for activated protein C resistance. Clin Lab Haematol 2001; 23:411.
  47. Hron G, Eichinger S, Weltermann A, et al. Prediction of recurrent venous thromboembolism by the activated partial thromboplastin time. J Thromb Haemost 2006; 4:752.
  48. Zakai NA, Ohira T, White R, et al. Activated partial thromboplastin time and risk of future venous thromboembolism. Am J Med 2008; 121:231.
  49. Baccarelli A, Martinelli I, Zanobetti A, et al. Exposure to particulate air pollution and risk of deep vein thrombosis. Arch Intern Med 2008; 168:920.
  50. Walenga JM, Fasanella AR, Iqbal O, et al. Coagulation laboratory testing in patients treated with argatroban. Semin Thromb Hemost 1999; 25 Suppl 1:61.