The 5 red flags that suggest your doctor isn't as good as you want them to be

Doctors around the world have been collaborating to give an 'insider's guide' to the warning signs you need to look out for when visiting your GP or specialist.

In a thread calling for 'serious replies only' from 'Doctors of Reddit', more than 3,000 comments have been left from those who claim to be working in the medical profession, and while we cannot verify their authenticity, some of the top answers make for some interesting – and sobering – reading.

From the doctor whose brother-in-law was misdiagnosed with heartburn before undergoing emergency heart surgery, to a healthcare user who recounts a worrying tale of a neurosurgeon who failed to spot a tumour on their spine that measured half a foot long: here are five red flags you might want to watch out for when you visit the doctor.

1. Beware a doctor who never says "I don't know"

The top-rated comment on the thread is from a specialist named 'jwilty', who warns that medicine is "insanely complex" – and that's precisely why a good physician should always be using resources (textbooks, journals, Google etc), both to refresh their existing knowledge and to keep themselves up to date. You should never show up to an appointment and expect an immediate and conclusive answer, unless your problem is straightforward. Saying "I don't know" does not make a doctor incompetent. It can be the reverse, in fact; because it shows they're being careful with your health, and recognise when they're out of their depth. If they always know the answer, the contributor warns, and especially if they are defensive when you ask questions, theycould be trying to hide their incompetence.

2. Ordering complex tests for every little problem

Being subjected to unnecessary examinations using expensive equipment – such as ultrasounds, MRIs, CT scans – may indicate a way for an individual doctor or laboratory to gain some extra funding from insurance companies, particularly in the US or in private practices, user 'jwilty' also writes. On the NHS, doctors cannot order simple – or complex – tests without justifying their need due to regulations or financial restraints. Either way, you should feel able to query the reasons behind unexpected examinations if you are going for a routine check-up and are otherwise fit and healthy. There may be very good reasons behind them, but you should feel empowered enough to understand your personal treatment plan and to proceed with the confidence that the doctor has your best interests at heart.

3. If they hear hooves – and think horses, not zebras

One user, named 'ElLocoS', a doctor who works in Brazil, offers a basic rule of thumb: 'The third doctor is always the best doctor'. They explain: "The real mistake is when you return with the same problem more than one time and they insist on their diagnosis, instead of continuing the investigation if the disease is not responding as expected to time or treatment." Another user, 'bilyl', adds: "You shouldn't keep looking for horses when the first specialist comes up negative. You certainly don't keep looking for horses when the second specialist's tests come up negative. That's when the zebra detectors come out." In short, don't be afraid to seek – or insist on – a second (or third) opinion.

4. If they ask the right questions but don't pay attention to the replies

User 'RingforJeeves' writes that some doctors can appear "lazy" if they have a script they work through, and, "so long as your replies don't completely throw them off, they just make their way through it without picking up on things like uncertainty when answering or nervousness or crossed wires". Similarly, he/she writes: "If you as the patient (or relative) have questions, or are prescribed something, or are booked in for a procedure and so on, you should at least understand the basics of why you need it and what it's for. If you go to the doctor not knowing what's wrong, and leave still not having a clue what it could be – but with a prescription or a referral – find another doctor who'll spend a few minutes actually informing you. Sometimes that might mean them telling you they don't know what it is, but that's a lot better than leaving thinking it must be totally fine, as the doctor didn't say anything other than "come back in a few days if you aren't feeling better"." However, a British NHS doctor also tells The Independent: "It's true – we do pretty much use a script for patients, but it is protocol-driven, and used to pick up on medical red flags. It is well-tested, verified questioning to enable us to make a proper diagnosis."

5. If they're "a bit of a maverick"

If your doctor distances themselves from the medical community, claims to be persecuted due to their methods or insists that they are a "maverick" with a unique treatment, writes user 'Henipah', steer clear: "This is a massive red flag that they are the outlier among evidence-based specialists and potentially dangerous."