Certainty in an Uncertain World - A Clinicians' Viewpoint of Sensitivity and Precision

Patrick Twomey

doi:10.2478/v10011-008-0005-4

Abstract

Certainty in an Uncertain World - A Clinicians' Viewpoint of Sensitivity and PrecisionClinical practice is evolving as research evolves from the bench to the bedside. Similarly, analytical technologies are improving on an annual basis. Rightly or wrongly, increased emphasis is now placed by clinicians on such investigations to the detriment of clinical history and examination. As people live longer, the prevalence of long-term conditions such as thyroid disease, cardiovascular disease and malignancies is increasing. Clinical biochemistry assays play an important part in the management (screening, diagnosis, prognosis and monitoring) of such conditions. This is reflected in the UK since 2004 by the primary care contract where over 100 of the 550 clinical points depend on clinical biochemistry assay results. Inter-assay results may differ due to bias, precision, assay specificity and assay sensitivity. To date, little emphasis has been placed on the potential clinical effect of precision. This presentation will explore the effect that assay precision can have on the management of important long-term conditions such as thyroid disease, cardiovascular disease and malignancies.

Highlights

Summary: Clinical practice is evolving as research evolves from the bench to the bedside
Clinical biochemistry assays play an important part in the management of such conditions
This is reflected in the UK since 2004 by the primary care contract where over 100 of the 550 clinical points depend on clinical biochemistry assay results

Summary

Introduction

Clinical practice is evolving as research evolves from the bench to the bedside. analytical technologies are improving on an annual basis. Clinical biochemistry assays play an important part in the management (screening, diagnosis, prognosis and monitoring) of such conditions. There are numerous situations where the result of a clinical biochemistry test is heavily relied upon and subsequently the result has dramatic consequences Some examples of these are TSH, Troponin and PSA this list is not exhaustive and many more exist. The precision of a PSA at low levels is critical to that seen around the cut-off Another example is troponin, an analyte unique to the world of clinical biochemistry. There are numerous interferences awaiting the unwary, HAMA, heterophilic antibodies, auto-antibodies, sample collection devices or additives, drugs, endogenous substances, to name but a few All of these factors can directly influence a result and mislead the clinician

Thyroid Stimulating Hormone

TSH Precision Profile

Prostate Specific Antigen

Findings

PSA Precision profile