Can it be ruled out? How?
My dad died at ucla med center last year in their icu. His initial microclots were thought to be from DVT related to a surgery. The microclots observed 2 months later at the time he was in the icu recovering for a different surgery (tee gone wrong) could not be traced back to DVT, but after multiple weeks of diagnostics, they were still unable to dx the source of the clots. They were not able to rule out a previous (mild) covid infection as the reason for the clots (he had been vaxed when he had a known infection a year earlier).