Factual error: In episode 414, "Living the Dream," the patient Evan is given a nerve function test. We see Kutner and Taub performing the test by puncturing Evan's legs with needles. Modern nerve function tests actually rely on electrical impulses from a small computerized device, with no needles necessary.
Suggested correction: House ordered an EMG (electromyography) to test for motor nerve entrapment. During an EMG, one or more small needles (electrodes) are inserted through the skin into the muscle. The electrical activity picked up by the electrodes is then displayed on an oscilloscope. An audio amplifier is used so the activity can be heard. When an electrode is inserted, a brief period of activity can be seen on the oscilloscope, but after that, no signal should be present.
Factual error: In an episode with a severely overweight patient who is thought to have diabetes, it is discovered he instead has Chagas disease. Cameron then informs the patient that he acquired this illness from his food when, in fact, Chagas disease is a protozoan that is spread through the bite of the triatomine bug.
Suggested correction: While the main vector for the infection is through the triatomine bug, Trypanosoma cruzi (the parasitic organism that causes the disease) can be transmitted through food, and thus Chagas was caused by the food the patient ate. It should also be noted that Trypanosoma cruzi is not transmitted by the bite of the triatomine bug, but rather through its feces, and it's only spreads once the feces enters the blood stream (which it can do through a bite site or scratching an open wound).
You Don't Want to Know - S4-E8
Factual error: Amber triggers a fire alarm by heating the sprinkler with her lighter. Unfortunately that fire sprinkler doesn't detect heat (or smoke). The sensor is located between the ceiling lamps, about two meters from the fire sprinkler. (00:09:00)
Suggested correction: Heat applied to the sprinkler would cause it to activate and spray water. All modern fire systems will detect this water pressure drop and activate the alarm.
