Does the medical community have a definitive test for als?

ALS Diagnosis: Als is a very difficult disease to diagnose. To date, no one test or procedure to ultimately establish the diagnosis of ALS is identified. It is through clinical examination and series of diagnostic tests, often ruling out other diseases that mimic als, that a diagnosis can be established.

Not really: This can be a challenging diagnosis to confirm, as other conditions could cause a similar presentation. A simple definitive blood or urine test doesn't exist. Diagnosis may require blood testing to exclude thyroid or Lyme or HIV, but EMG, imaging of spine, and even muscle biopsy may be required to confirm.