I use to be a medical intepreter (for about 3 years), it was a great experience-- just loved it. Now, depending on where you work your experience is going to vary. For example, I worked in the ER of one hospital and what you saw there was very different from when I use to work out in the clinics (of the same hospital). In the ER you experienced everything, saw everything and gained a great deal of knowledge. Working out in the clinics (I use to float around clinics) depending on the clinic I was in (whether it was pedi, geriatrics, internal med., etc) you would pretty much see the same thing over and over again to the point where you memorized the questions some of the PAs and MDs would ask patients. Overall, I enjoyed the ER a lot more since it was so fast-paced, graphic, and just picked up so much, however, the clinics were more relaxed and I had more time for myself and picked up some clerical work experience.
As far as pay is concerned, it just depends on your experience. To be certified many hospitals/clinics have contracted an outside company where you are sent to take an exam to see if you are qualified to interpret (the last exam I took, took 3 hours and it was in both Spanish and English). I took three exams (since I worked in 3 different hospitals) and each exam pretty much consisted of the same thing: 1. a general part that tested your language/grammatical skills (make sure you could pretty much read and identified the grammatically correct sentence), 2. a definition part where they give you a medical term and you define it, 3. listening part where you listen to a short message that then asks you a question and you choose the correct answer on your test (m/c), and finally an oral portion where you are asked simple questions (your name, where you work, how to give directions, etc), to identified some body parts or give the definition to some medical terms, and lastly give instructions on how to take a particular medication (I had to be able to explain the instructions to follow when using a nasal spray). Depending on your score you would be either a Level I or II interpreter (with Level II being the higher pay).
Finally, depending on where you work is how much you will get paid. Larger hospitals tend to pay well and are in more need of interpreters than clinics. In Dallas, Tx (where I worked) the average pay for a Level II interpreter was anywhyere from $16-$22 depending on experience. No experience will most definately guarantee you the lower pay. (Level I pays anywhere from $13-$17). Also, not all hospitals list their interpreters under the title of Interpreters, at one hospital I worked for we were called Guest Relations Representatives, in another Translators and finally Patient Advocates. I wish you luck and I know you will enjoy being an interpreter it is so fulfilling and rewarding.
