Some symptom patterns appear only with standing, exertion, meals, or during an episode. When the condition of measurement is part of the clinical question — and when a dynamic test adds nothing.

A reference interval is not a verdict. How reference ranges, clinical decision limits, treatment targets, and personal baselines differ — and why 'optimal range' is usually the wrong shortcut.

Nerve conduction studies assess large fibers and may be normal in small fiber neuropathy. How symptoms, examination, skin biopsy, and functional testing are combined.

MCAS diagnosis requires more than a symptom list. Review the consensus criteria, event-related mediator testing, treatment response, and the alternatives that must be considered.