Educational content only. Diagnosis of these conditions is complex and requires specialist consultation. Many standard tests (e.g., basic blood count) appear normal in these diseases, despite the patient's severe condition.
This is a diagnosis of exclusion. IOM (2015) or Canadian Consensus Criteria (CCC) are used.
2-day Cardiopulmonary Exercise Test (2-day CPET) objectively confirms PEM.
MCAS is a "Diagnostic Chameleon" – it affects multiple systems at once. Testing is difficult because mediators disappear from the blood very quickly.
Often normal! Elevated mainly in mastocytosis or during anaphylaxis.
Very unstable. Blood must be chilled immediately.
24-hour urine collection. Often the best indicator of a flare.
Positive response to treatment (H1/H2 blockers) is often an official part of diagnosis when lab tests are inconclusive.
Visible on standard lumbar MRI (low-lying conus medullaris).
Common in EDS. MRI often described as "normal", even though the filum terminale is fibrotic and tight.
Standard supine MRI is often inconclusive. In this position, muscles are relaxed, and gravity does not press the skull against the spine, so the instability "hides" (vertebrae return to place).
Examination in sitting or standing position, preferably in flexion/extension. This is the only way to see how vertebrae compress the spinal cord under movement.
X-ray in motion (video), showing vertebrae "sliding" in real-time.
Manual Traction Test: Does pulling the head up (by a physiotherapist) bring sudden relief? If so, it suggests a mechanical component.
A simple screening tool to assess generalized joint hypermobility (a hallmark of EDS). The maximum score is 9 points.
Passive dorsiflexion of the little finger beyond 90 degrees.
Passive apposition of the thumb to the flexor aspect of the forearm.
Hyperextension of the elbow beyond 10 degrees.
Hyperextension of the knee beyond 10 degrees.
Placing hands flat on the floor with knees fully extended.
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Remember: This is just a screening test. Diagnosis is made by a doctor (geneticist/rheumatologist) based on full hEDS criteria.