Initial Symptoms: Man with cardiac arrest
Diagnosis: Lupus (House) + blood transfusion error (Kutner)

Contributions by Team
House (2): Realizes bleeding during MRI was caused by magnet ripping swallowed key out of patient's intestines, diagnosis for lupus
Cameron (N/A): Not part of differential
Chase (N/A): Not part of differential
Cole (1): Sees fluid in lungs and bleeding in kidney and thigh
Foreman (2): Sees immunoglobulin levels are low, stops House from irradiating patient
Kutner (3): Finds bleeding around patient's heart, diagnosis for bad blood transfusion, sees kidneys are shutting down
Taub (0): None
Thirteen (0): None
Volakis (0): None

Notes: It's unclear whether it was Taub, Volakis, Kutner or Thirteen who performed the ultrasound to find bleeding around the patient's heart when he lost consciousness. I've awarded credit to Kutner because he was the one who told House they did it, implying (but not proving) it was his idea.
Kutner originally suggests "bad blood" and "tainted blood", which throughout the episode seems to imply receiving the wrong blood type as well as infected blood. House realizes the patient received the wrong blood type during his transfusion because lupus made his blood type test results erroneous.
House tests the blood the patient was transfused with by injecting himself with it. I considered awarding him credit, but in the end decided this particular test wasn't necessary for the lupus diagnosis.
Cole was fired at the end of the episode.

Labels: Season 4