Yes, SG, not sire whether it is still tested, but it measures the amount of"solids" that are secreted in the urine......in other words how efficient the kidneys are in filtering.
As a medical student, a favourite trick of one of the extrovert Consultants would test for sugar in the urine by putting his finger in the urine speciman and then popping his finger in his mouth. He would then ask one of the students to do the same thing, which they reluctantly did, with grimaces on their faces.
He would then say, that if they had paid attention they would have noticed that he placed his ring finger in the urine, but put his middle finger in his mouth.