One of the difficulties in addressing the large differences in use of laboratory tests1 is to produce robust protocols, supported by high level evidence, for the use of these tests. A working group has been established to improve the knowledge base in laboratory medicine and is working with Sir Muir Gray, director of clinical knowledge, process and patient safety for the National Programme for Information Technology.2 The initiative has brought together contributions from a range of professional associations and clinical authors to improve knowledge in the use of laboratory testing. It is collating answers to about 100 frequently asked questions in primary care on the use of laboratory tests and is presenting these through a range of media, using a standardised literature search targeted towards clinical guidelines and evidence based reviews. The complete question-answer sets are being developed into prompts, reminders, and alerts to help doctors and nurses while they are treating patients. This series of articles has been constructed around relevant clinical cases which illustrate some of the problems that can arise in using, or not using, laboratory tests, linked to the guidance points obtained from these answers.

The key points are a synthesis of existing guidelines on the subjects concerned, and in most cases originate from the consensus of national or international experts. They are “the best we can get” at present, although the answering process has revealed questions that justify further research and could have a large impact on policies for use of tests. To enrich this debate, guidance is accompanied by evidence notes highlighting the strengths or weaknesses of the evidence base supporting the guidance.

This article presents and discusses two typical cases seen in a district hospital lipid clinic. Laboratories differ in the profiles of tests they offer, and some will add tests …