What is the test for a civil rights claim in the context of medical malpractice cases?

"In order to state a cognizable [civil rights] claim, a prisoner must allege acts or admissions sufficiently harmful to evidence deliberate indifference to serious medical needs." Estelle v. Gamble, 429 U.S. 97, 106. The indifference to medical needs must be substantial; inadequate treatment due to negligence or inadvertence, or differences in judgment between an inmate and medical personnel does not constitute cruel and unusual punishment. Estelle, 429 U.S. at 106; Shields v. Kunkel, 442 F.2d 409, 410 (9th Cir.1971).