First level test: B12, A1c, SPEP with immunifixation electrophoresis initially, TSH, CBC, and CMP. Extensive testing not necessary if known DM or ETOH Second level test: EMG/NCS: EMG will differentiate between nerve or muscle disorder, NCS differentiates bw axonal or demyelinating neuropathy. consider Lyme titer in Endemic area CXR if suspect sarcoid