Browse the corpus
Walk the evidence base by book and chapter — the raw source passages that ground Ask, Differential, and the rest.
1 passage
Don't repeat HbA1c testing sooner than the guideline interval when a recent result exists (every 3 years if normal; annually if stable prediabetes). Setting: a recent HbA1c result exists (normal within the last 3 years, or stable prediabetes within the last year) and a repeat is ordered sooner than the guideline interval without a change in clinical status or therapy Why: HbA1c reflects ~3 months of glycaemia and changes slowly; repeating it inside the guideline interval in stable patients cannot change management and adds cost. Consider instead: retrieve and act on the prior result; retest at the guideline interval or when clinical status or therapy changes Source: American Society for Clinical Laboratory Science / ASCP (Choosing Wisely) (Choosing Wisely, US, null).