Expert testimony is generally required in a medical malpractice case to establish the standard of care and causation.  The expert must practice in the same field of medicine, but not necessarily in the precise specialty.[1]

“[T]o practice ‘in the same field’ means that a pharmacist may not define the standard of care for a physician  and that a physician may not do so for a pharmacist. There is no general rule that prohibits a specialist from testifying regarding the standard of care applicable to a general practitioner or a specialist in one area from testifying about another area.” [2]

Expert testimony is not required where the determination of negligence does not require technical medical expertise, such as amputation of the wrong limb or leaving a foreign object in a patient during surgery.[3]

This is not a substitute for legal advice.  If you believe you have been the victim of medical malpractice you should consult with an attorney.

[2] Morton v. McFall, 128 Wn. App. 245 at 253 (2005), citing White v. Kent Med. Ctr., Inc. , 61 Wn. App. 163 , 173, 810 P.2d 4 (1991); Eng v. Klein , 127 Wn. App. 171 , 172, 110 P.3d 844 (2005).

[3] Miller v. Jacoby, 145 Wn.2d 65, 33 P.3d 68 (2001); Bauer v. White, 95 Wn.App. 663, 976 P.2d 182 (1989).