It’s still not entirely clear if Paul Pierce had alcohol in his system during his arrest last week … as TMZ Sports has learned cops are still waiting on his blood test results.

The NBA legend, as you know, was taken into custody by the California Highway Patrol on Oct. 7 … after authorities say they found him asleep at the wheel of his Range Rover SUV while on Highway 101 in Los Angeles.

Officers claimed Pierce exhibited signs of alcohol impairment — and he was ultimately arrested on suspicion of DUI.

On Monday, a spokesperson for the CHP told us they haven’t yet gotten results that establish Pierce’s BAC during the incident.

The rep added “a local crime lab” is responsible for processing the sample, and a timeline for the return of the results is not known.

For Pierce’s part, he seemed to deny he was drunk during the run-in with cops … writing in a statement on Threads on Oct. 9 that the whole matter stemmed from him being “old” and “tired.”

“Imagine being stuck in stand still traffic for 45 mins and falling asleep ,” he wrote. “I took this picture that night because I never been in stand still traffic for this long.”

“I’m old, I’m tired, and I fell asleep ,” he continued. “I’m good y’all thanks for the love.”