Overview
A coagulation profile is a grouped order of screening assays that evaluate extrinsic/common (PT/INR) and intrinsic/common (aPTT) pathways, frequently including fibrinogen.
Clinical Importance
To screen for coagulopathy before procedures or in bleeding evaluation
To monitor selected anticoagulant effects (method- and drug-dependent)
Specimen Requirements
- Specimen: platelet-poor plasma prepared from whole blood
- Tube: light-blue top; 3.2% sodium citrate (0.109 mol/L)
- Anticoagulant ratio: 9:1 blood-to-citrate (CLSI H21); fill to the tube fill line
- Handling: invert gently; transport promptly; avoid traumatic draws and line heparin contamination
- Processing: centrifuge to platelet-poor plasma per institutional protocol before testing
- Stability: assay-specific (CLSI H21). aPTT is generally less stable than PT; do not exceed validated time/temperature limits for the ordered tests.
Analytical Method
Citrated plasma is recalcified with pathway-specific reagents; time to fibrin clot detection is measured by mechanical or photo-optical coagulometers.
Instruments Used
Automated analyzers
- Sysmex CS / CN coagulation analyzers
- Werfen / Instrumentation Laboratory ACL TOP coagulation analyzers
- Siemens Healthineers BCS coagulation analyzers
- Stago STA Compact / STA R Max coagulation analyzers
Manual methods
- Manual tilt-tube clotting methods (selected reference/backup contexts)
Reference Values
Typical adult SI examples below follow widely published international hematology practice (e.g., Dacie and Lewis; Henry's). Always interpret against the method- and demographics-specific interval printed on the patient report (CLSI EP28-A3c). Neonatal, pediatric, pregnancy, and altitude intervals differ.
Each component has reagent-specific intervals; see PT, INR, aPTT, and fibrinogen entries.
Interpretation
Critical and significant-risk limits are institution-defined (CLSI GP47). Confirm the local call list. Textbook examples are not universal thresholds.
Critical values
- Markedly prolonged clotting times may be critical per institutional policy
Common Causes of Increased Results
- Prolonged PT and/or aPTT indicate pathway defects, inhibitors, anticoagulant effect, or pre-analytical artifact; follow mixing studies when indicated
Common Causes of Decreased Results
- Shortened times are uncommon and often pre-analytical or analytic artifacts; interpret cautiously
Clinical Significance
- Preoperative hemostasis screen when indicated
- Bleeding workup starting panel
- Selected anticoagulant monitoring contexts
Factors Affecting Results
Pre-analytical
- Underfilled citrate tube (excess anticoagulant prolongs clotting times)
- Overfilled tube or clot in specimen
- Hematocrit >55% may require adjusted citrate volume (CLSI H21 guidance)
- Delayed processing or improper storage beyond assay stability
- Heparin contamination from line draws
Analytical
- Reagent lot / instrument calibration differences
- Lipemia, hemolysis, or icterus interfering with photo-optical endpoints
Post-analytical
- Applying another laboratory's reference interval
- Misreading INR therapeutic targets as untreated reference intervals
Advantages and Limitations
Advantages
- Rapid pathway-level screen
- Standardized collection under CLSI H21 principles
Limitations
- Normal screen does not exclude all bleeding disorders (e.g., mild factor deficiency, platelet function disorders)
- Drug effects vary by reagent sensitivity
Clinical Pearls
A coagulation 'panel' is only as good as the citrate fill; reject underfilled blue-tops before chasing factor deficiencies.
References
Authoritative textbooks, guidelines, and reviews supporting this laboratory test reference. Verify reference intervals, critical limits, and method details against institutional protocols and current guideline editions.
Textbooks
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2021.
- Rodak BF, Carr JH. Rodak's Hematology: Clinical Principles and Applications. 6th ed. Elsevier; 2020.
- Hoffbrand AV, Moss PAH, Pettit JE. Essential Haematology. 8th ed. Wiley-Blackwell; 2019.
- McKenzie SB, Williams JL. Clinical Laboratory Hematology. 4th ed. Pearson; 2022.
- Bain BJ, Bates I, Laffan MA. Dacie and Lewis Practical Haematology. 12th ed. Elsevier; 2017.
- Kaushansky K, et al. Williams Hematology. 10th ed. McGraw-Hill; 2021.
- Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018.
CLSI and Professional Guidelines
- Clinical and Laboratory Standards Institute. Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays and Molecular Hemostasis Assays; Approved Guideline. CLSI document H21-A5. CLSI; 2017.
- Clinical and Laboratory Standards Institute. One-Stage Prothrombin Time (PT) Test and Partial Thromboplastin Time (PTT) Test; Approved Guideline. CLSI document H47-A2. CLSI; 2008.
- Clinical and Laboratory Standards Institute. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Standard. CLSI document EP28-A3c. CLSI; 2010.
- Clinical and Laboratory Standards Institute. Management of Critical- and Significant-Risk Results. CLSI guideline GP47-Ed1. CLSI; 2015.
Frequently Asked Questions
Common questions about using this Coagulation Profile laboratory test Medical Laboratory Library reference in Medical Laboratory Science education.
What is the Coagulation Profile laboratory test reference used for?
This Medical Laboratory Library page summarizes the clinical importance of Coagulation Profile. Review the Clinical Importance section for why the test is ordered in laboratory medicine practice.
Where can I find Coagulation Profile specimen requirements?
See the Specimen Requirements section on this page for specimen information related to Coagulation Profile. Confirm collection details against your laboratory protocol.
Where are Coagulation Profile reference values listed?
See the Reference Values section on this Laboratory Library page. Reference ranges can vary by method and population, so verify intervals with your laboratory.
How do I interpret Coagulation Profile results?
Use the Interpretation section for laboratory interpretation framing, including increased and decreased result patterns when provided. Do not treat educational text as a patient-specific diagnosis.
What analytical method is used for Coagulation Profile?
See the Analytical Method section for principle and method notes. Method details may differ by instrument and institutional SOP.
Are related laboratory tests linked from Coagulation Profile?
Yes. The Related Laboratory Tests section lists connected references for continued lookup in the Medical Laboratory Library.
How can I continue learning after reading Coagulation Profile?
Use Continue learning links on this page for related Academy lessons, medical laboratory quizzes, or laboratory case studies when available for this Hematology topic.
What are the clinical pearls for Coagulation Profile?
See the Clinical Pearls section for concise laboratory practice notes associated with Coagulation Profile. Apply pearls alongside institutional protocols.
Reading progress
Awards XP once after you have meaningfully reviewed this article.