TL-positive

TL-positive was a blood type that Gallifreyans had. The First Doctor once had to give the Xing surgeon Aldridge two litres of his TL-positive blood for a surgery. (PROSE: A Big Hand for the Doctor)

Steven Taylor thought the First Doctor's unidentified blood type barely even resembled blood as seen in humans. (AUDIO: An Ideal World) According to Dr Lomax, the Third Doctor's blood had a blood type unidentifiable as human blood, as shown by its platelet stickiness. (TV: Spearhead from Space)