PRACTICAL LABORATORY EDUCATION
About Pathology Uncertainty
Clear explanations of measurement, statistics and analytical quality for professionals across laboratory medicine.
Why this site exists
A laboratory result is useful when its performance is understood in relation to the decision it supports. Pathology Uncertainty helps laboratory professionals ask the right questions about measurement, choose suitable evidence and recognise the limits of a conclusion.
The site connects measurement uncertainty, analytical performance specifications, method verification, method comparison, internal quality control and external quality assessment. Its focus is practical reasoning across laboratory disciplines: what does this number mean, what evidence supports it, and what should happen next?
Stephen MacDonald PhD FRCPath
Stephen is a Consultant Clinical Scientist in Specialist Haemostasis at Cambridge University Hospitals NHS Foundation Trust. His clinical and research work brings together assay performance, measurement uncertainty and the interpretation of laboratory results.
He completed his PhD at the University of Hertfordshire in December 2025. His research examined imprecision, analytical performance and measurement uncertainty in the laboratory assessment of thrombotic thrombocytopenic purpura. The thesis is available through the University’s research archive, where it was deposited in 2026.
Stephen tutors applied haemostasis and thrombosis and medical laboratory statistics at the University of Greenwich. He also writes educational articles for Pathology in Practice and develops online learning material. His specialist clinical background informs the examples and questions, while this website addresses principles relevant across laboratory medicine.
Selected research and educational writing
These publications provide examples of the research and teaching behind the site. Journal articles, professional educational writing and the doctoral thesis are identified separately; the selection is not a complete bibliography.
Measurement Uncertainty in the Hemostasis Laboratory
MacDonald S. Seminars in Thrombosis and Hemostasis. Published online 2025. Journal review article.
Measurement uncertainty in the VWF-ADAMTS13 axis: the challenges of adding a calculated measurand in the haemostasis laboratory
MacDonald S. Journal of Laboratory and Precision Medicine. 2023;8:5. Journal review article; first published online in December 2022.
Method comparison studies: a look at acceptability criteria
MacDonald S. Pathology in Practice. December 2020. Professional educational article.
Studies of Imprecision, Performance and Measurement Uncertainty in Laboratory Assessment of Thrombotic Thrombocytopenic Purpura
MacDonald SG. Doctoral thesis, University of Hertfordshire. Repository record dated 2026.
How to use the guides
Start with the question you need to answer, then follow the assumptions, examples and linked sources. Numerical teaching examples are labelled as fictional or constructed. They explain a principle; they do not validate a particular examination or supply an automatic acceptance criterion.
Sources are linked so that readers can distinguish an original explanation from the underlying guidance. Where a link provides only a standard’s public scope, the full document is needed for its procedural requirements. An update date records a content change; it should not be read as a claim of independent peer review.
Scope and independence
Pathology Uncertainty is an independent educational website. Material published here does not represent an endorsement by Stephen’s employer, a professional body or an accreditation body. It supports professional understanding and does not replace a locally approved procedure, specialist judgement or the applicable full guidance.
Questions, teaching enquiries and corrections
Use the contact page for teaching enquiries or to identify an unclear statement, calculation error or outdated source. Include the page address and the passage concerned so that the issue can be located. The privacy policy explains how information submitted through the site is handled.