The barrette in Amber's hair when she is on the bus is different to the one in her hair when she is in the bar with House.
When House and Wilson are transporting Amber in the ambulance, she goes into 'V-fib' (ventricular fibrillation). However, the ECG is showing an atrial fibrillation pattern, not ventricular. Also, the heart rate is shown as 145 on the monitor but the ECG pattern indicates a heart rate well over that.
When trying to diagnose Amber, the team rules out diet pills because she is in liver failure, which couldn't have been caused by the pills. The liver failure could easily have been caused by massive blunt trauma from the bus crash that took out both her kidneys.
When Thirteen prints the results for her Huntington's test, the paper can be seen emerging from the front of the printer with the bottom of the page leading accompanied by the sound of a laser or thermal printer, but the printer she's seen to be using should have paper emerging from the top of the printer with the top of the page leading, and the appearance of the printed text would only be plausible coming from a much-louder dot-matrix printer.
When Thirteen and Kutner were searching the apartment, they should have found the note Amber left for Wilson, saying she was going to pick up House. Had House known Amber came to pick him up, they would have arrived at the diagnosis sooner... not that it would have made any difference to the outcome.
When Foreman and Taub turn Amber to check the small of her back, Foreman switches from Amber's right side to join Taub on her left side, pushing on her leg to roll her over. For patient safety, either doctor would have grasped at the patient's shoulder and hip, turning Amber toward them (so she doesn't roll off the bed) while the other doctor checks her back.