Ronaldo has been self-isolating since he tested positive for the virus while away on international duty with Portugal this month.
The 35-year-old attacker had hoped to feature in Juve's Group G fixture against Barca, meaning a chance to once again go up against Lionel Messi, but needed a negative test 24 hours prior to kick-off in Turin.
In an Instagram post on Wednesday, Ronaldo said he was "feeling good and healthy", but the five-time Ballon d'Or winner then followed that up with a comment questioning the accuracy of the Polymerase chain reaction (PCR) tests.
"PCR IS BULLSH*T", he wrote, before eventually deleting the comment.
PCR tests are the most common way to test for coronavirus and is believed to be the most accurate. The test is performed by collecting a swab or sputum sample - mucus coughed up from the lungs - from the nose or throat. The sample is then enlarged in a machine and inspected for coronavirus genetic material.
Juventus confirmed the forward's absence from the squad for the midweek clash in Turin, while centre-back Leonardo Bonucci was included in Andrea Pirlo's list, however, having passed a late fitness test.
Juve are unbeaten in all competitions so far this season, but have won just two matches and drawn four. Pirlo's side started their Champions League campaign with a 2-0 win against Dynamo Kyiv in Ukraine, while Barca beat Hungarian outfit Ferencvaros 5-1 at Camp Nou last week.