Is semiannual calibration verification required if the laboratory is performing calibration at least once every six months?  

Semiannual calibration verification is not required when the laboratory performs a calibration protocol using 3 or more levels of calibration materials that include a low, mid, and high value at least once every 6 months. After calibration, quality control should be performed and documented to verify the calibration protocol was successful.  Please see 'Note 1' and 'Note 2' at QSA.02.03.01 EP 3 in the Quality System Assessment chapter of the Laboratory Accreditation Manual for additional information regarding calibration verification.