How Your Doctor Makes Decisions About Your Health

I remember going to see my GP long before I became a doctor. I’ve always been curious about how things work, and the doctor’s office was no exception. What kind of mysterious process allows doctors to determine what’s going on with your health? Just by talking to you, laying hands on you—how do they decide what tests to do? How does it all work?

Years later, when I entered medical school, I was excited to finally learn these “secrets.” But as with many complex skills, the better you get at it, the harder it becomes to explain exactly how you do it. I believe this lack of understanding is a common source of friction and misunderstanding between doctors and patients. In this post, I’ll give you a glimpse into how medical decision-making works in practice.

Emergency vs Non-Emergency Situations

When doctors make decisions, we generally categorise cases as either emergencies or non-emergencies. This distinction matters because the approach and priorities differ significantly.

In a true emergency—situations that are immediately life-threatening, such as severe injuries, heavy bleeding, cardiac arrest, or breathing issues—our priority is to save lives. We don’t stop to gather much information initially; instead, we focus on interventions that support the airway, breathing, and circulation (the ABCs). We gather only limited information to help guide immediate actions and determine what urgent treatments or tests might be needed. It’s only after the immediate threat is addressed that we slow down and gather more detailed information.

For everything else—the types of consultations you might be more familiar with, like visiting your GP with a new symptom—we take a different approach. These visits allow more time for observation, history-taking, and examination, which all contribute to building a clearer picture of what might be going on.

Observation and History-Taking

Doctors begin gathering information from the moment they see you. We observe your appearance, how you walk from the waiting area, how you stand, your colour, breathing, speech, and overall demeanour. Observation is a powerful tool, and it becomes more valuable with experience. We might also have the chance to review your medical history in advance, which helps us get a head start on what might be affecting you.

Then, there’s history-taking, which is where most of the diagnostic impression is formed. I’ll ask questions about your symptoms—when they began, how they’ve progressed, and other relevant details. Sometimes, I’ll ask questions that might seem unrelated, but they’re often crucial clues. I’ll also ask about past medical history, medications, home situation, or employment if they’re relevant to your current problem.

Physical Examination and Forming a “Differential Diagnosis”

The examination process often begins as soon as I see you, but formally, it involves taking some measurements, such as heart rate, breathing rate, blood pressure, oxygen levels, and temperature. These help me gauge your overall health and urgency level. I then conduct a physical examination, focusing on areas relevant to your complaint but also taking a quick “once-over” of the main body systems.

By the time I finish examining you, I usually have a “differential diagnosis”—a prioritised list of possible conditions. The most likely ones go to the top, but I keep other possibilities in mind to avoid premature conclusions. Being too quick to reach a diagnosis can lead to “diagnostic bias,” which might cause me to miss something important.

Deciding on Investigations and Tests

The differential diagnosis helps me decide if any investigations or tests are necessary. Often, no additional tests are needed, as observation, history, and examination give me enough information. For any test I order, I consider the potential risks and benefits. X-rays and scans involve radiation exposure, which can slightly increase cancer risk over a lifetime. Blood tests, while generally low-risk, can sometimes create unnecessary worry or lead to further invasive procedures if the results aren’t clearly interpreted. So, I ask myself: will this test actually change what I do for you?

Many people imagine blood tests as producing a “diagnosis slip.” In reality, the results are just a list of numbers that have to be carefully interpreted within the broader context of your symptoms and overall health.

The Balance of Risks, Benefits, and Time

Decision-making often boils down to a balance of risks and benefits. Should I perform a test if the potential risks aren’t justified by the potential gain in knowledge or treatment options? The answer depends on factors like the seriousness of your possible condition, the reliability of the test, and any potential side effects of treatment. For example, if I suspect a blood clot (DVT) but believe a calf strain is more likely, over-testing or pre-emptively prescribing blood thinners could cause unnecessary harm.

And then there’s the role of time—the ultimate variable. Health conditions evolve. Symptoms can improve or worsen regardless of any intervention, sometimes despite everyone’s best efforts. This is why follow-up and monitoring are also important tools.

In Conclusion

Understanding how doctors make decisions can help bridge the gap between patient expectations and medical reality. In hindsight, some patients may feel that different choices should have been made, but when you walk through the steps taken based on the information available at the time, you often find that the decisions were appropriate. Unfortunately, “the retrospectoscope” is not a tool available to us in the moment.

That’s a quick tour of how medical decision-making works. Feel free to reach out if anything resonated with you or if you have questions about this complex and fascinating process.