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Semin Thromb Hemost 2019; 45(01): 022-035
DOI: 10.1055/s-0038-1677018
Review Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

How to Optimize Activated Partial Thromboplastin Time (APTT) Testing: Solutions to Establishing and Verifying Normal Reference Intervals and Assessing APTT Reagents for Sensitivity to Heparin, Lupus Anticoagulant, and Clotting Factors

Emmanuel J. Favaloro
1   Diagnostic Haemostasis Laboratory, Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
2   Sydney Centres for Thrombosis and Haemostasis, Westmead, New South Wales, Australia
,
Geoffrey Kershaw
2   Sydney Centres for Thrombosis and Haemostasis, Westmead, New South Wales, Australia
,
Soma Mohammed
1   Diagnostic Haemostasis Laboratory, Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
,
Giuseppe Lippi
3   Department of Haematology, NSW Health Pathology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
4   Section of Clinical Biochemistry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy
› Author Affiliations
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Publication History

Publication Date:
10 January 2019 (online)

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Abstract

The activated partial thromboplastin time (APTT) assay is a very common coagulation test, used for several reasons. The test is conventionally used for assessing the contact factor (intrinsic) pathway of blood coagulation, and thus for screening deficiencies in this pathway, most typically factors VIII, IX, and XI. The APTT is also sensitive to contact factor deficiencies, including factor XII, prekallikrein, and high-molecular-weight kininogen. The APTT may also be elevated in a variety of conditions, including liver disease, vitamin K deficiency, and disseminated intravascular coagulation. The APTT can also be used for monitoring unfractionated heparin (UFH) therapy, as well as for screening lupus anticoagulant (LA) or for assessing thrombosis risk. Which of these separate uses is important to a given laboratory or clinician depends on the laboratory and the clinical context. For example, UFH sensitivity is important in hospital-based laboratories, where UFH therapy is used, but not in hospital-based laboratories where low-molecular-weight heparin (LMWH) is largely employed or where UFH may be assessed by anti-factor Xa testing, or in private/community laboratories not associated with a hospital system. High sensitivity to (low levels of) factors VIII, IX, and XI is generally preferred, as their deficiencies are clinically significant. Also preferred, but not usually achieved, is low sensitivity to factor XII and other contact factors, as these deficiencies are usually asymptomatic. Nevertheless, a good knowledge of factor sensitivity is usually needed, if only to help explain the reasons for a prolonged APTT in a given patient, or whether factor testing or other investigation is required. A good working knowledge of reagents sensitivity to LA is also advisable, especially when the reagent is used as part of a LA test panel, or else as a “general-purpose screening reagent.” The current report is aimed at providing some guidance around these questions, and is intended as a kind of “how to” guide, that will enable laboratories to assess APTT reagents in regard to their sensitivity to heparin, LA, and clotting factors. The report also provides some advice on generation of normal reference ranges, as well as solutions for troubleshooting prolonged APTTs, when performing factor testing or searching for inhibitors.

Keywords

activated partial thromboplastin time - factor sensitivity - heparin sensitivity - lupus anticoagulant sensitivity
 

  • References

  • 1 Favaloro EJ, Lippi G, Koutts J. Laboratory testing of anticoagulants: the present and the future. Pathology 2011; 43 (07) 682-692
    CrossrefPubMedGoogle Scholar
  • 2 Favaloro EJ. How to generate a more accurate laboratory-based international normalized ratio: solutions to obtaining or verifying the mean normal prothrombin time and international sensitivity index. Semin Thromb Hemost 2019; 45 (01) 10-21
    Article in Thieme ConnectPubMedGoogle Scholar
  • 3 Favaloro EJ. Optimizing the verification of mean normal prothrombin time (MNPT) and international sensitivity index (ISI) for accurate conversion of prothrombin time (PT) to international normalized ratio (INR). Methods Mol Biol 2017; 1646: 59-74
    CrossrefPubMedGoogle Scholar
  • 4 Poli G, Castiglioni P, Montagnana M, Favaloro EJ, Lippi G. Troubleshooting an isolate prolongation of activated partial thromboplastin time in a patient with acute myocardial infarction-a paradigmatic case report. Ann Transl Med 2016; 4 (21) 426
    CrossrefPubMedGoogle Scholar
  • 5 Levy JH, Szlam F, Wolberg AS, Winkler A. Clinical use of the activated partial thromboplastin time and prothrombin time for screening: a review of the literature and current guidelines for testing. Clin Lab Med 2014; 34 (03) 453-477
    CrossrefPubMedGoogle Scholar
  • 6 Kershaw G. Performance of activated partial thromboplastin time (APTT): determining reagent sensitivity to factor deficiencies, heparin, and lupus anticoagulants. Methods Mol Biol 2017; 1646: 75-83
    PubMedGoogle Scholar
  • 7 Lippi G, Favaloro EJ. Activated partial thromboplastin time: new tricks for an old dogma. Semin Thromb Hemost 2008; 34 (07) 604-611
    Article in Thieme ConnectPubMedGoogle Scholar
  • 8 Vandiver JW, Vondracek TG. Antifactor Xa levels versus activated partial thromboplastin time for monitoring unfractionated heparin. Pharmacotherapy 2012; 32 (06) 546-558
    CrossrefPubMedGoogle Scholar
  • 9 Marlar RA, Clement B, Gausman J. Activated partial thromboplastin time monitoring of unfractionated heparin therapy: issues and recommendations. Semin Thromb Hemost 2017; 43 (03) 253-260
    Article in Thieme ConnectPubMedGoogle Scholar
  • 10 Baluwala I, Favaloro EJ, Pasalic L. Therapeutic monitoring of unfractionated heparin - trials and tribulations. Expert Rev Hematol 2017; 10 (07) 595-605
    CrossrefPubMedGoogle Scholar
  • 11 Favaloro EJ, Wong RC. Antiphospholipid antibody testing for the antiphospholipid syndrome: a comprehensive practical review including a synopsis of challenges and recent guidelines. Pathology 2014; 46 (06) 481-495
    CrossrefPubMedGoogle Scholar
  • 12 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 (07) 495-504
    CrossrefPubMedGoogle Scholar
  • 13 Ames PR, Graf M, Archer J, Scarpato N, Iannaccone L. Prolonged activated partial thromboplastin time: difficulties in discriminating coexistent factor VIII inhibitor and lupus anticoagulant. Clin Appl Thromb Hemost 2015; 21 (02) 149-154
    CrossrefPubMedGoogle Scholar
  • 14 Pengo V, Tripodi A, Reber G. , et al; Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. Update of the guidelines for lupus anticoagulant detection. J Thromb Haemost 2009; 7 (10) 1737-1740
    CrossrefPubMedGoogle Scholar
  • 15 Keeling D, Mackie I, Moore GW, Greer IA, Greaves M. ; British Committee for Standards in Haematology. Guidelines on the investigation and management of antiphospholipid syndrome. Br J Haematol 2012; 157 (01) 47-58
    CrossrefPubMedGoogle Scholar
  • 16 CLSI. Laboratory Testing for the Lupus Anticoagulant; Approved Guideline. CLSI document H60-A. Wayne, PA: Clinical and Laboratory Standards Institute; 2014
    Google Scholar
  • 17 CLSI. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Proposed Guideline—Third Edition. CLSI document C28–P3. Wayne, PA: Clinical and Laboratory Standards Institute; 2008
    Google Scholar
  • 18 CLSI. One-Stage Prothrombin Time (PT) Test and Activated Partial Thromboplastin Time (APTT) Test; Approved Guideline—Second Edition. CLSI document H47–A2. Wayne, PA: Clinical and Laboratory Standards Institute; 2008
    Google Scholar
  • 19 Lippi G, Mengoni A, Manzato F. Sensitivity of two commercial reagents for prothrombin time and activated partial thromboplastin time to isolate coagulation factor deficiencies. Eur J Lab Med 1999; 7: 61-65
    PubMedGoogle Scholar
  • 20 Lawrie AS, Kitchen S, Efthymiou M, Mackie IJ, Machin SJ. Determination of APTT factor sensitivity--the misguiding guideline. Int J Lab Hematol 2013; 35 (06) 652-657
    CrossrefPubMedGoogle Scholar
  • 21 Lippi G, Salvagno GL, Montagnana M, Lima-Oliveira G, Guidi GC, Favaloro EJ. Quality standards for sample collection in coagulation testing. Semin Thromb Hemost 2012; 38 (06) 565-575
    Article in Thieme ConnectPubMedGoogle Scholar
  • 22 Adcock Funk DM, Lippi G, Favaloro EJ. Quality standards for sample processing, transportation, and storage in hemostasis testing. Semin Thromb Hemost 2012; 38 (06) 576-585
    Article in Thieme ConnectPubMedGoogle Scholar
  • 23 Lippi G, von Meyer A, Cadamuro J, Simundic AM. Blood sample quality. Diagnosis (Berl) 2018. doi: 10.1515/dx-2018-0018. [Epub ahead of print]
    PubMedGoogle Scholar
  • 24 Franchini M, Liumbruno GM, Bonfanti C, Lippi G. The evolution of anticoagulant therapy. Blood Transfus 2016; 14 (02) 175-184
    PubMedGoogle Scholar
  • 25 Lippi G, Mattiuzzi C, Cervellin G, Favaloro EJ. Direct oral anticoagulants: analysis of worldwide use and popularity using Google trends. Ann Transl Med 2017; 5 (16) 322
    CrossrefPubMedGoogle Scholar
  • 26 Blennerhassett R, Favaloro EJ, Pasalic L. Novel (oral) anticoagulant challenges in surgery. Semin Thromb Hemost 2017; 43 (07) 706-715
    Article in Thieme ConnectPubMedGoogle Scholar
  • 27 Favaloro EJ, Pasalic L, Lippi G. Replacing warfarin therapy with the newer direct oral anticoagulants, or simply a growth in anticoagulation therapy? Implications for pathology testing. Pathology 2017; 49 (06) 639-643
    CrossrefPubMedGoogle Scholar
  • 28 Favaloro EJ, McCaughan G, Pasalic L. Clinical and laboratory diagnosis of heparin induced thrombocytopenia: an update. Pathology 2017; 49 (04) 346-355
    CrossrefPubMedGoogle Scholar
  • 29 Favaloro EJ. Laboratory tests for identification or exclusion of heparin induced thrombocytopenia: HIT or miss?. Am J Hematol 2018; 93 (02) 308-314
    CrossrefPubMedGoogle Scholar
  • 30 Manzato F, Mengoni A, Grilenzoni A, Lippi G. Evaluation of the activated partial thromboplastin time (APTT) sensitivity to heparin using five commercial reagents: implications for therapeutic monitoring. Clin Chem Lab Med 1998; 36 (12) 975-980
    PubMedGoogle Scholar
  • 31 Bjornsson TD, Wolfram KM. Intersubject variability in the anticoagulant response to heparin in vitro. Eur J Clin Pharmacol 1982; 21 (06) 491-497
    CrossrefPubMedGoogle Scholar
  • 32 Hirsh J, Bauer K, Donati MB, Gould M, Samama MM, Weitz JI. Parenteral anticoagulants: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008; 133: 141S-159S
    CrossrefPubMedGoogle Scholar
  • 33 Lippi G, Plebani M, Favaloro EJ. Interference in coagulation testing: focus on spurious hemolysis, icterus, and lipemia. Semin Thromb Hemost 2013; 39 (03) 258-266
    Article in Thieme ConnectPubMedGoogle Scholar
  • 34 Olson JD, Arkin CF, Brandt JT. , et al; Laboratory Monitoring of Unfractionated Heparin Therapy. College of American Pathologists Conference XXXI on laboratory monitoring of anticoagulant therapy: laboratory monitoring of unfractionated heparin therapy. Arch Pathol Lab Med 1998; 122 (09) 782-798
    Google Scholar
  • 35 Lippi G, Favaloro EJ. Recent guidelines and recommendations for laboratory assessment of the direct oral anticoagulants (DOACs): is there consensus?. Clin Chem Lab Med 2015; 53 (02) 185-197
    PubMedGoogle Scholar
  • 36 Favaloro EJ, Pasalic L, Curnow J, Lippi G. Laboratory monitoring or measurement of direct oral anticoagulants (DOACs): advantages, limitations and future challenges. Curr Drug Metab 2017; 18 (07) 598-608
    PubMedGoogle Scholar
  • 37 Gosselin RC, Adcock DM, Bates SM. , et al. International Council for Standardization in Haematology (ICSH) recommendations for laboratory measurement of direct oral anticoagulants. Thromb Haemost 2018; 118 (03) 437-450
    Article in Thieme ConnectPubMedGoogle Scholar
  • 38 Van Cott EM, Smock KJ, Chen D, Hsu P, Zantek ND, Meijer P. Testing for dabigatran and rivaroxaban by clinical laboratories. Am J Hematol 2016; 91 (11) E464-E467
    CrossrefPubMedGoogle Scholar
  • 39 Kamal AH, Tefferi A, Pruthi RK. How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults. Mayo Clin Proc 2007; 82 (07) 864-873
    CrossrefPubMedGoogle Scholar
  • 40 Morris WH, Kumar A. What is the significance of an isolated elevated activated partial thromboplastin time in the preoperative setting?. Cleve Clin J Med 2007; 74 (Suppl. 01) S13-S15
    CrossrefPubMedGoogle Scholar
  • 41 Kershaw G. Performance and interpretation of mixing tests in coagulation. Methods Mol Biol 2017; 1646: 85-90
    PubMedGoogle Scholar