Module COAG-02 · Version 1.0
Secondary Hemostasis and the Meaning of Screening Tests
A working tour of the cell-based model of coagulation paired with what PT, aPTT, thrombin time, fibrinogen, and anti-Xa actually challenge in vitro, built around a guided case with an isolated prolonged aPTT.
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Who this module is for
Clinical laboratory scientists and students who draw, run, or interpret coagulation screening tests and want to reason from reagent behavior rather than a memorized cascade chart.
Learning objectives
- Explain initiation, amplification, propagation, thrombin generation, fibrin formation, and regulation in the cell-based model of hemostasis.
- Map PT and aPTT reagent systems to the broad factor groups they challenge without treating the classic cascade as literal in-vivo anatomy.
- Recognize screening-test sensitivity limits and the role of specimen and reagent variables when interpreting a coagulation screen.
How completion works
Mark every required section done and answer every knowledge check in those sections correctly. The final save completes the module automatically.
Sources
14 sources
1. Centers for Medicare & Medicaid Services. 42 CFR §493.1253, Standard: Establishment and verification of performance specifications. Federal regulation.
Source note · federal regulation
2. Centers for Medicare & Medicaid Services. 42 CFR §493.1269, Standard: Hematology. Federal regulation.
Source note · federal regulation
3. Clinical and Laboratory Standards Institute. H47: One-Stage Prothrombin Time (PT) Test and Activated Partial Thromboplastin Time (APTT) Test, 3rd ed., H47Ed3E, 2023. Consensus standard.
Source note · consensus standard
4. Clinical and Laboratory Standards Institute. H21: Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays, 6th ed., H21Ed6E, 2024. Consensus standard.
Source note · consensus standard
5. College of American Pathologists. Hematology, Coagulation, and Clinical Microscopy Checklist, HEM.37870 Reference Intervals (Phase II). CAP Accreditation Program, 12.09.2025 edition.
Source note · accreditation standard
6. Hoffman M, Monroe DM III. A cell-based model of hemostasis. Thrombosis and Haemostasis. 2001;85(6):958-965. Peer-reviewed review.
Source note · peer-reviewed literature
7. Hoffman M. Why do patients bleed? Transfusion. 2017;57(10):2397-2404. Peer-reviewed review.
Source note · peer-reviewed literature
8. Furie B, Furie BC. Coagulation tests. In: Walker HK, Hall WD, Hurst JW, eds. Clinical Methods, 3rd ed. NCBI Bookshelf, 1990. Reference review.
Source note · laboratory reference
9. Muszbek L, Yee VC, Hevessy Z. Factor XIII: structure, activation, and interactions with fibrinogen and fibrin. Thrombosis Research. 1999;94(5):271-305. Peer-reviewed review.
Source note · peer-reviewed literature
10. Lowe GDO. Physiological haemostasis. In: Mechanisms of Vascular Disease. NCBI Bookshelf, 2011. Reference review.
Source note · laboratory reference
11. Lippi G, Favaloro EJ, Buoro S. Pre-analytical issues in the haemostasis laboratory: guidance for the clinical laboratories. Thrombosis Journal. 2017;15:6. Peer-reviewed guidance review.
Source note · peer-reviewed literature
12. Bronić A, et al. National recommendations for blood collection, processing, performance and reporting of results for coagulation screening assays. Biochemia Medica. 2019;29(2):020503. Professional society guidance.
Source note · professional society guidance
13. Tripodi A, et al. Position paper on laboratory testing for patients on direct oral anticoagulants. Blood Transfusion. 2018;16(5):462-470. Professional society guidance.
Source note · professional society guidance
14. Roche Diagnostics. Reagents on the cobas t 511 and cobas t 711 coagulation analyzers, product overview, including PT Rec, aPTT, Clauss fibrinogen, and TT reagent families. Manufacturer labeling.
Source note · manufacturer labeling