Overview
This LabPedia entry refers specifically to the historical Lee-White whole-blood clotting time (WBCT): freshly drawn non-anticoagulated venous blood is placed in glass tubes and timed until a solid clot forms on tilting.
It is distinct from activated clotting time (ACT), capillary-tube clotting methods, prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT). Those assays must not share descriptions or decision limits with Lee-White WBCT.
Status: historical / obsolete for routine laboratory practice. Modern heparin monitoring and pathway screening use validated aPTT and/or anti-Xa protocols (and ACT only in specific procedural settings when locally defined).
Clinical Importance
Historically used as a crude global hemostasis test and, in some eras, for heparin monitoring
Not recommended for modern routine coagulation evaluation or heparin monitoring
Specimen Requirements
- Specimen: fresh whole blood without anticoagulant, timed immediately after venipuncture
- Historical Lee-White method: glass tubes (often multiple tubes), controlled temperature, and timed tilting to a clot endpoint
- Tube material matters: glass contact activation differs from siliconized or plastic surfaces, which can markedly prolong observed times
- Not a citrate plasma assay and not interchangeable with PT, aPTT, TT, or ACT specimens
Analytical Method
Contact activation on glass surfaces initiates clotting in non-anticoagulated whole blood. The recorded endpoint is formation of a firm clot on tube tilting.
Results vary substantially with temperature, tube material (glass vs siliconized), blood volume, traumatic draw, and operator endpoint judgment.
Instruments Used
Automated analyzers
- No routine automated coagulation analyzer module for Lee-White whole-blood clotting time
Manual methods
- Lee-White whole-blood clotting time in glass tubes (historical)
Reference Values
No numeric reference interval is published on this page. Historical Lee-White expected times vary widely across sources and technique details (glass vs siliconized tubes, temperature, and endpoint rules).
Because method identification and technique dominate the result, a single universal minute-range would be scientifically unsafe. Do not use historical clotting-time values for current patient-care decisions.
This entry intentionally omits a numeric example rather than inventing or copying an unverified universal range.
Interpretation
Common Causes of Increased Results
- Historically, prolongation was a nonspecific finding and may have been associated with marked factor deficiency, heparin effect, or technique artifact; it does not localize a modern pathway defect
Common Causes of Decreased Results
- Short times are not used as a modern interpretive category for Lee-White testing
Clinical Significance
- Educational and historical reference only in most settings
- Not a substitute for PT, aPTT, thrombin time, fibrinogen, anti-Xa, or procedural ACT when those assays are indicated
Factors Affecting Results
Pre-analytical
- Temperature during observation
- Glass versus siliconized or plastic tube surfaces
- Traumatic draw or tissue-factor contamination
- Delay between draw and start of timing
Analytical
- Observer subjectivity at the clot endpoint
- Tube number and tilting interval differences between historical protocols
Post-analytical
- Confusing Lee-White whole-blood clotting time with ACT, PT, aPTT, or thrombin time
- Applying any published historical minute-range as a modern universal normal
Advantages and Limitations
Advantages
- Historical teaching value for contact activation and global clot formation concepts
Limitations
- Insensitive, poorly reproducible, and obsolete for routine care
- Replaced for pathway screening by PT and aPTT
- Replaced for heparin monitoring by validated aPTT and/or anti-Xa methods (ACT remains a separate, procedure-specific assay when used)
Clinical Pearls
If a request says only “clotting time,” identify the method before interpreting anything. Lee-White whole-blood clotting time is historical; do not confuse it with ACT or plasma PT/aPTT.
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.
- Bain BJ, Bates I, Laffan MA. Dacie and Lewis Practical Haematology. 12th ed. Elsevier; 2017.
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 Whole-Blood Clotting Time (Lee-White, Historical) laboratory test Medical Laboratory Library reference in Medical Laboratory Science education.
What is the Whole-Blood Clotting Time (Lee-White, Historical) laboratory test reference used for?
This Medical Laboratory Library page summarizes the clinical importance of Whole-Blood Clotting Time (Lee-White, Historical). Review the Clinical Importance section for why the test is ordered in laboratory medicine practice.
Where can I find Whole-Blood Clotting Time (Lee-White, Historical) specimen requirements?
See the Specimen Requirements section on this page for specimen information related to Whole-Blood Clotting Time (Lee-White, Historical). Confirm collection details against your laboratory protocol.
Where are Whole-Blood Clotting Time (Lee-White, Historical) 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 Whole-Blood Clotting Time (Lee-White, Historical) 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 Whole-Blood Clotting Time (Lee-White, Historical)?
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 Whole-Blood Clotting Time (Lee-White, Historical)?
Yes. The Related Laboratory Tests section lists connected references for continued lookup in the Medical Laboratory Library.
How can I continue learning after reading Whole-Blood Clotting Time (Lee-White, Historical)?
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 Whole-Blood Clotting Time (Lee-White, Historical)?
See the Clinical Pearls section for concise laboratory practice notes associated with Whole-Blood Clotting Time (Lee-White, Historical). Apply pearls alongside institutional protocols.
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