Prognosis vs Diagnosis – Difference Between Prognosis and Diagnosis
The difference between prognosis and diagnosis is that a prognosis is used to determine the projected outcome of an illness or disease, whereas a diagnosis is used to identify a disease that a person is currently suffering from via observation and analysis.
Because you will hear these two terms used together so regularly, we have taken the time to provide you with a full breakdown of their individual definitions as well as to lay out a quick reference table for you that will help you to easily summarize prognosis vs diagnosis. Read on for everything you need to know.
Definition of Prognosis – So What Is Prognosis?
The prognosis definition is a medical opinion or a way of assessing or finding out what kind of disease or illness a person is suffering from.
The word prognosis originates in Greece and can be loosely translated as meaning a way of knowing something. The word pro when isolated also means before. So, a prognosis by its very nature comes before something else.
A prognosis is ultimately what comes before a specific diagnosis. Though we will cover the latter word in greater detail shortly, it would be virtually impossible to give someone an effective diagnosis without a prognosis being carried out beforehand.
The main difference between prognosis and diagnosis is that a prognosis is an evaluation and assessment. It involves a medical practitioner diving deep into a person’s current physical state, their everyday activities, and their symptoms in order to gain a better understanding of the different elements that may interact negatively with one another to create some kind of definitive end result.
That end result is, of course, a diagnosis because it is the conclusion of the assessment (prognosis) that we have carried out on the patient.
A prognosis can also sound like a diagnosis sometimes because it is voiced as an opinion. This can sometimes be a speculative or vague opinion, or it can be a relatively firm and assertive one, making it sound conclusive.
Here is an example of a speculative prognosis. “Based on everything that you’ve told me, I feel like it’s likely that you might be suffering from disease A, or it could be B too … but that’s a little less likely.”
This is an example of a more assertive and self-assured prognosis. “Based on what I’ve heard and seen today, I’m almost certain that you’re suffering from disease A.”
What separates prognosis vs diagnosis in either instance is that even though the doctor in the first sentence thinks he knows what the disease is and the second doctor is almost certain that he knows, we can observe that we are still just watching an evaluation process that results in educated opinions. Certainty usually comes after testing and liaison with specialists.
A diagnosis would then come once any reasonable doubt had been removed from the prognosis process and the only end result that we were left with would be to conclude that the patient was definitely suffering from a certain condition or illness.
Definition of Diagnosis – So What Is Diagnosis?
The diagnosis definition is the identification of a specific illness that a person is suffering from.
It is probably immediately clear when reading the above definition that when we are giving a diagnosis, we must be very specific. There is no opinion involved at this stage or even an evaluation or underlying process.
What separates diagnosis vs prognosis is that we are being very definitive with what we are saying in a diagnosis. This is a conclusive word, meaning that it follows a precursory (something that comes before) process. That precursory process is a prognosis.
We can only arrive at a specific diagnosis once we have performed an in-depth prognosis. Even after a prognosis, it usually takes further analysis and opinions from specialists to be able to arrive at a diagnosis.
The reason why is that medical practitioners have to be incredibly careful before giving a diagnosis to a patient. The difference between diagnosis and prognosis is that you can perform a prognosis and offer a medical opinion without causing direct harm to the patient, but once a diagnosis has been reached, the opposite is true.
If we were to give someone an incorrect diagnosis, then they could be given the wrong type of treatment, which could actually have a negative impact and make them worse. Once a well-researched diagnosis has been given, this is the final conclusion as long as the diagnosis is accurate and allows us to provide effective treatment.
We can see the distinction between diagnosis vs prognosis in these typical sentences. “Based on the test results we received, we can now diagnose you with illness A and begin your treatment program.” “After evaluating your symptoms and discussing them with a specialist in this area, we’re now in a position where we can diagnose you with disease B.”
It is worth noting that even after an effective prognosis process and discussion with a specialist, it is very unlikely that an accurate diagnosis would be provided without some kind of medical testing occurring first.
To help you with the question what is a diagnosis and to help you compare it to prognosis, we have laid out a visual reference guide in the next section.
What Is the Main Difference Between Prognosis vs Diagnosis?
The following table clearly shows the difference between diagnosis and prognosis in a format that you can come back to anytime you get stuck on this subject for a quick refresh.
| Word | Diagnosis | Prognosis |
| Definition | An identification of a specific disease or illness | A medical opinion on what disease or illness a person could potentially be suffering from based on their current circumstances or symptoms |
| Used to | Form an educated conclusion that will allow us to effectively deliver a treatment program to a patient | Assess and evaluate a person’s current physical circumstances so that we can deliver an effective diagnosis |
| Which comes first? | A diagnosis comes after a prognosis | A prognosis comes before a diagnosis |
| Origin | Greece | Greece |
| Translation | “To conclusively distinguish between two possibilities” | “Before knowledge” |
| Dependency on age | A diagnosis is not age dependent. It is simply formed through analysis of prevalent symptoms. | A prognosis may need to be altered based on age due to physiological changes at certain age ranges and what these changes signify. |
| Duration | A quick process | A prolonged process |
| Examples | “Based on your prognosis and test results, we can definitely diagnose you with condition A.” | “Now that I’ve learned more about you and your situation, I feel that you are likely suffering from condition B. We’ll now perform further tests and discuss your situation with specialists to form an effective diagnosis and begin your treatment.” |
So What Is the Difference Between Diagnosis and Prognosis? – Conclusion
Finally, you should now be able to answer the question what is a prognosis with ease as well as being able to identify what makes a diagnosis completely different in nature.
If you are ever trying to summarize the two, just remember that a prognosis is the evaluation process that allows us to reach an effective diagnosis. In summary, the fundamental difference between the two is that one is a process, while the other is a conclusion.
