PPBS is post prandial blood sugar, basically they check your sugar 2 hours after a meal. My gynac used it to monitor for gestational diabetes. Its a simple blood test, nothing to be scared of.
I did this test a lot because i had gestational diabetes. They check fasting and then 2 hours after eating to see how your body handles sugar. Once you know the numbers, managing diet becomes much easier honestly.
Its just the after meal sugar check, super routine in pregnancy. You eat normally, wait two hours, give a blood sample. Dont stress, almost everyone gets sugar screening done.