2 weeks ago my blood pH level was -11 the doc tried to take arterial blood gases but couldn't. He was confused by -11 pH level. What could cause it?

PH. pH range runs only from 0 (very acidic) to 14 (very basic/alkali). The body's normal pH is right around 7.35ish. I am confused by the -11 reading as well as there is no such possibility to have that as a result. Maybe it was a result of equipment malfunction, or an error message by the computer.