I need some help with the coding of the PH Study and the Manometry. I am using CPT 91034 for the 24 hour PH study and 91037 for the Manometry are these the correct codes? Also we are being told we cannot bill for both studies does anyone know if that is true. Our patient comes in and has the Manometry and then before they leave the tube is inserted for the PH study and the come back the next day which is when the test is actually read, so we are billing the Manometry on day one and the PH study on day 2. If any body can give a good answer and where I can find the coding guidelines that would be great.