Here’s a potted guide. The letters themselves are called postnomials. They are qualifications and can indicate membership or fellowship of an organisation that can award them.
MBBS – Bachelor of Medicine, Bachelor of Surgery. This is the degree issued by most medical schools in the UK after 5 years of medical training at University.
MBChB – Bachelor of Medicine, Bachelor of Chirugery (another term for surgery). Some medical schools in the UK issue this degree.
BSc – Bachelor of Science. This is a undergraduate degree (meaning that you do not need a degree already before you can enrol) which takes 3 years at University. A BSc in certain subjects can be obtained by an additional year taken half way through medical school training.
MD – Doctor of Medicine. In Britain this is a postgraduate research degree (meaning you need to already have a degree before you can enrol) which requires 2 years of full time study and the writing of a thesis. In the USA, this is the basic degree in medicine. In India, this is a postgraduate taught degree, rather than a research degree.
PhD – Doctor of Philosophy. Some doctors undertake a PhD, usually a 3 year research degree.
MRCP – Member of the Royal College of Physicians. Membership is awarded after passing a postgraduate exam. All doctors specialising in internal medicine must pass this exam before entering subspecialty training eg in Cardiology.
FRCP – Fellow of the Royal College of Physicians. Members of the Royal College of Physicians can be elected to become a fellow if they have distinguished themselves in the field of medicine. Not all Consultants are invited to become fellows.
FHRS – Fellow of the Heart Rhythm Society. Fellowship of this US based organisation is offered to those who have extensive training and specialise in heart rhythm disorders.
CCDS – Certified Cardiac Device Specialist. This is a qualification offered by the International Board of Heart Rhythm Examiners. This requires evidence of completing training in pacemaker and defibrillator therapies, followed by a 5 hour exam, which is valid for 10 years. I recertified in 2019.
CEPS-AC. Certified Electrophysiology Specialist in Adult Cardiology. This qualification is awarded by the International Board of Heart Rhythm Examiners and again lasts 10 years.
CCT – Certificate of completion of training. This is awarded to doctors when they have completed their training and are eligible to enter the GMC Specialist register or the GP register. All permanent Consultant appointments require entry on the GMC Specialist register, though locum Consultants may not be on the Specialist register. The letters CCT are not recognised as a postnomial and are therefore not usually used.
There are a whole host of other qualifications for doctors in different fields.
Surgeons for example have MRCS and FRCS, Membership and Fellowship of the Royal College of Surgeons, which is awarded after passing a postgraduate exam. For some reason in the UK this means that they are addressed as Mister / Miss / Mrs rather than Doctor. They don’t do this in other countries.
General Practitioners also have the MRCGP (Membership of the Royal College of General Practitioners) exam and can do other qualifications in many specialties, for example Obstetrics and Gynaecology (DRCOG).
Universities also have titles such as Professor / Reader / Senior Lecturer and these reflect teaching or research roles.
My qualifications include MBBS(Hons). Hons is short for honours. These were awarded because I graduated in the top 10% of my year at Medical school. I also did an additional Bachelors of science degree (BSc) in Neuroscience. After qualifying I passed the MRCP exam in 2003. I was awarded an MD(Res) in 2016 with King’s College London for echo imaging to research the effect of pacing on heart function. I also passed both the IBHRE exams in pacing and electrophysiology. I retook the pacing exam in 2019 after 10 years, I scored in the top 1% so have been invited to be an IBHRE ambassador and mentor for other candidates. I was elected a Fellow of the Royal College of Physicians in 2018 as recognition of my research, teaching and my work on College committees. I was elected a Fellow of the Heart Rhythm Society as I have exemplified my commitment to Cardiac Electrophysiology.