A visit to the doctor, to a clinic, nursing facility or hospital means talking to a dizzying number of people about medical issues. People ask for history, check your blood pressure and vital signs, take your blood, give you injections...who the heck are all these people?
MA or CMA - this is a medical assistant, most often seen in an outpatient clinic working with providers there. They work under the supervision of doctors and nurses. Their scope of practice in most states where they are regulated include clerical tasks, taking history, vital signs, assisting the provider during exams, taking specimens, and may be trained in phlebotomy (taking blood). Some states allow them to do additional simple procedures and operate equipment under the supervision of a physician, but they are never allowed to interpret results. What is a medical assistant? They are usually the liaison between patients and their primary care providers, and may be mistakenly referred to as "nurse". Note that it is illegal for an MA or CNA to present themselves in such a manner. Calling yourself a nurse is a crime.
CNA - this is a Certified Nursing Assistant, most often seen in home health or inpatient facilities such as nursing homes or hospitals. CNAs work under the supervision and delegation of an RN, and provide hands-on bedside care such as taking vital signs, bathing and cleaning the patient, transferring the patient and assisting them with movement and self-care tasks like toileting and shaving. They also have the important responsibility of tracking bowel movements and skin condition in severely impaired patients, alerting the RN when changes are noted before much larger problems occur. They may also do dressing changes and daily wound care in some states. Both of the above require similar education, the primary difference is the location of their work and the tasks that are delegated to them. Both have differences in regulation and licensure (if any) varying by state. Differences between CNAs and MAs
LPN or LVN - this is a Licensed Practical Nurse or Licensed Vocational Nurse, terminology varies by state. An LPN *is* a nurse. They are licensed to provide nursing care, and are found in most places you will find doctors and nurses. They work under the supervision of a physician or RN and may have duties delegated by an RN. Limitations on practice by LPNs vs RNs are in areas that require clinical judgement, and in more advanced care settings. Many states limit the role of LPNs and do not allow them to administer IV medications or narcotics. Working as an LPN . LPNs are used to help keep healthcare costs down because it is much less expensive to have a group of LPNs working under the supervision of one RN than to employ RNs only.
RN - Registered Nurse. This is a nurse who has completed either an associates/certificate program or a bachelors degree in nursing, and passed the national licensure exam (NCLEX) as well. They perform all nursing tasks, supervise and may delegate to LPNS, MAs or CNAs, and may obtain advanced specialty training to increase their scope of practice in particular areas. While an RN has the broadest scope of practice of all the above listed, they also have the highest level of responsibility. The RN is responsible for not only their own scope, but they accept the responsibility of tasks that are delegated to them by physicians. An RN is responsible for ensuring the appropriateness of treatments, medications, etc that they have been ordered to give and is accountable along with the prescriber if the are wrong. Scope of practice is determined on a state-by-state basis, and requirements for continuing education vary. My specialty is Hospice and Palliative Care (CHPN). Some states allow me to pronounce a patient dead, some states require that I contact a physician to get that pronouncement, some states require the coroner to be notified, etc as an example of variations on scope of practice. As far as the other letters you will see after RN on a nurse's badge, they will generally designate their specialty certifications and may also include their education (MSN - masters of science in nursing, etc).
APRN - Advanced practice RNs. These are RNs who have continued their education to a master's or doctorate in a particular specialty area and by doing so have increased their legal scope of practice. APRN These providers practice medicine under their own licenses, and in most states do not require supervision of a physician to practice. The financial advantages of having a DNP versus an MD in roles that do not require the scope of practice of a physician are the same as those for hiring an LPN versus an RN. In the past, a Master's degree was the minimal educational requirement in most states for a Nurse Practitioner (APRN). Many states have changed that requirement to a doctorate, and there has been a push to make this a national requirement. So the Nurse Practitioner who sees you at the clinic may well be Doctor Nurse! http://www.nursepractitionerschools.com/faq/dnp-requirement-for-np This is similar to the change in requirements for pharmacists, who are now required to have a doctorate as well.
PA - Physician Assistant. PAs are masters degree trained medical providers who attend a specialized Physician Assistant program. http://www.nursepractitionerschools.com/faq/np-vs-physician-assistant PAs work under the supervision of a physician, and are frequently found in the same settings that you would find Nurse Practitioners. The primary difference between the two is that an NP can diagnose and treat without the supervision of a physician.
DO - Doctor of Osteopathy. A Doctor of Osteopathy is a physician who has received their degree in medicine from a School of Osteopathic Medicine. They are licensed in each state as physicians and have the same scope of practice as MDs. DOs primarily see their practice as different from traditional medicine in the emphasis on a holistic patient-centered, versus disease-centered focus. An example: Oregon License Definitions Note that the scope of practice in Oregon is identical to that of an MD, with the addition of musculoskeletal manipulation.
MD - A licensed Doctor of Medicine, graduate of an accredited medical program and licensed by the state to practice medicine. May be found anywhere medicine is practiced. There are a vast number of specialties of medicine. A couple that regularly confuse people are Internist (a doctor with advanced training in Internal Medicine) and Intern (a medical doctor who is doing their clinical training for their licensure). Hospitalist - this is a fairly new specialty, physicians who specialize in treating patients who are hospitalized, coordinating all the specialties involved and ensuring that the patient is followed appropriately after discharge. Note that it is also illegal to impersonate a physician!
***Disclaimer: The above are the opinions and research of myself, a retired nurse. None of the above constitutes medical advice or definitive anything, is representative of the US, et cetera ad nauseum. Consult your local state medical board or nursing board for definitions, limitations, requirements and scope of practice.