APPENDIX 5
Employing Clinical Laboratory Studies in the Diagnosis of ALS

The demonstration of the presence of a pathogenic, relevant gene mutation can assist in the diagnosis of ALS (such as SOD-1).

There are no clinical laboratory tests which confirm the diagnosis of non-genetically determined ALS.

Clinical Laboratory tests that may be abnormal in otherwise typical ALS:

• Muscle enzymes
  (serum creatine kinase [unusual above ten times upper limit of normal], ALT, AST, LDH)
• Hypochloremia, increased bicarbonate
  (related to advanced respiratory compromise)
• Serum creatinine
  (related to loss of skeletal muscle mass)
• Elevated CSF protein
  (uncommonly more than 100mg/dl)

Clinical Laboratory tests that may be abnormal in ALS with Laboratory Abnormalities of Uncertain Significance (ALS-LAUS) and ALS Mimic Syndromes:

• Autoantibodies (including antineuronal)
• Hormonal abnormalities
• Bone marrow/lymph node biopsy (lymphoma may be associated with CSF protein >1g/dl
• Evidence of infection
• Blood and urine lead levels
• Hexoseaminidase A/B

Clinical laboratory features inconsistent with the diagnosis of ALS:

• There is no clinical laboratory finding which, if present with the proper clinical and electrophysiological signs of ALS and appropriate neuroimaging studies, rules out the diagnosis of ALS.

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