Diagnosis vs Prognosis

By Dr. Sanchari Sinha Dutta, Ph.D. Reviewed by Danielle Ellis, B.Sc.

What is diagnosis?
What is prognosis?
Recent advancements in clinical diagnosis
References
Further reading

Diagnosis refers to the clinical detection of a disease through a series of examinations. Prognosis, on the other hand, predicts disease course and therapeutic outcomes.

Image Credit: ARMMY PICCA/Shutterstock.com What is diagnosis?

Diagnosis is the process of detecting a disease through its signs and symptoms. Medical professionals make the final diagnosis of a disease by collecting and analyzing a patient’s medical history and conducting necessary physical examinations and laboratory tests. 1

An accurate and timely diagnosis of a disease is the key to patients’ wellbeing and positive health outcomes. Diagnostic information can also influence public health decisions, such as payment policies, resource allocations, and research priorities. 2

Disease diagnosis is a complex, patient-centered, collaborative process that initiates the patient’s decision to seek medical assistance. The first diagnostic step taken by a physician is to collect and interpret the patient’s medical history and subsequently determine a working diagnosis. 2

The working diagnosis may include a differential diagnosis (a list of potential diagnoses) or a single potential diagnosis. A physician typically considers a list of potential diagnoses to interpret a patient’s symptoms and subsequently refine the list while gathering more information during the diagnostic process. 2

Diagnostic refinement or modification of the working diagnosis is done by collecting more information through the patient’s physical examination and laboratory testing. This leads to the selection of one or two potential diagnoses that most accurately explain the patient’s signs and symptoms. This process is called diagnostic verification. 2

The diagnostic verification process is particularly important for patients who need to undergo invasive or risky diagnostic testing or treatment options, such as surgery. The basic ideology is that a patient should only be exposed to these risks if there is a reasonable chance that these testing or treatment options will be informative and will likely improve patient outcomes. 2

A final diagnosis is made by physicians when they feel satisfied with the fact that all necessary information has been collected to explain the patient’s health problem. The entire diagnostic process is intended to be broadly applicable, including the provision of mental health care. 2

A physician may consult with other physicians to get additional expertise about a patient’s health problem. This may help confirm or reject the working diagnosis or may provide additional information required for therapeutic decision-making.

Similarly, if a physician does not have the clinical expertise to diagnose or treat a particular health problem, they can refer the patient to other physicians with the required expertise.

Transparent communication between the physician, patient, and patient’s family members is also an important factor during the diagnostic process. A physician should accurately inform the patient and family members not only about the final diagnosis but also about the working diagnosis and its refinement.     What is prognosis?

Prognosis refers to the prediction of disease course and clinical outcomes or the prospect of recovery from a disease or injury. The prognosis of a disease or injury may vary according to the patient’s age, sex, and race and applied treatment. 3

Prognosis is determined on the basis of certain factors, including the patient’s demographic characteristics (age, sex, race, or ethnicity), general health conditions, disease stage or grade, presence of comorbidities, and treatment outcomes. These factors are called prognostic factors. 4

Disease can have a good or excellent prognosis if the causative factor associated with disease onset is clearly visible and can be easily mitigated. However, a poor or uncertain prognosis is typically observed for diseases with severe and persistent symptoms or diseases with elusive causative factors. 4 What is My Prognosis? Using information on Life Expectancy to Make Important Decisions Play Related StoriesEnsuring sustainable and responsible use of AI in healthcareHow perceived benefits and risks affect public willingness to pay for healthcareIdentifying barriers to effective cardiac rehabilitation

A patient can have a varied prognosis during the disease course. The prognosis is typically uncertain at the time of initial diagnosis. The prognosis can be guarded or fair during treatment and subsequently can become good or excellent after successful treatment completion. 4 

Prognosis is a crucial factor in therapeutic decision-making, as well as discussing the opinions of patients or their family members regarding disease management. For a disease with a poor prognosis, a patient may decide not to undergo risky or invasive treatment options, such as surgery. This is especially applicable to cases where the chances of improvement in life expectancy are minimal despite undergoing risky or invasive treatments. 3    

The accuracy of disease prognosis typically depends on the experience of the prognosticator. However, recent advancements in prognosticating methods have allowed even inexperienced but informed clinicians to determine prognosis using the existing literature and statistical means. 3

An ideal team for determining prognosis should include an experienced physician and a person with literature screening and statistical knowledge. An in-depth analysis of existing evidence is highly important during the prognostic process. Both seasoned clinicians and average clinicians can improve the accuracy of their prognoses for a given situation using this type of evidence-based medicine. 3 Recent advancements in clinical diagnosis

The development of advanced diagnostic tools has significantly improved the healthcare system and immensely helped healthcare professionals identify and understand various diseases with high accuracy. 5

The most recent advancement in medical science is the integration of machine learning into diagnostic tools. Machine learning algorithms can rapidly analyze large medical datasets with high accuracy and substantially increase the precision of disease diagnosis. 5

Clinical Applications of Spatial Biology in Disease Diagnosis and Treatment

Machine learning algorithms can significantly reduce the risk of diagnostic mistakes, which may occur during the diagnostic process of rare diseases or diseases with unnoticeable symptoms. 5

Machine learning-based analysis of microscopic images has made it easier to distinguish between malignant cells and normal cells, as well as to identify novel biomarkers in a time-efficient manner. Deep learning, a form of machine learning, is also gaining popularity in the clinical field. References 

1. Definition of diagnosis – NCI Dictionary of Cancer Terms – NCI. February 2, 2011. Accessed August 13, 2024. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/diagnosis
2. Balogh EP, Miller BT, Ball JR, et al. The Diagnostic Process. In: Improving Diagnosis in Health Care. National Academies Press (US); 2015. Accessed August 13, 2024. https://www.ncbi.nlm.nih.gov/books/NBK338593/
3. Hansebout RR, Cornacchi SD, Haines T, Goldsmith CH. How to use an article about prognosis. Can J Surg. 2009;52(4):328-336. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2724829/
4. Prognosis – an overview | ScienceDirect Topics. Accessed September 7, 2024. https://www.sciencedirect.com/topics/medicine-and-dentistry/prognosis
5. Ahsan M, Khan A, Khan KR, Sinha BB, Sharma A. Advancements in medical diagnosis and treatment through machine learning: A review. Expert Syst. 2024;41(3):e13499. doi:10.1111/exsy.13499 https://onlinelibrary.wiley.com/doi/10.1111/exsy.13499
6. Ahsan MM, Luna SA, Siddique Z. Machine-Learning-Based Disease Diagnosis: A Comprehensive Review. Healthcare. 2022;10(3):541. doi:10.3390/healthcare10030541 https://www.mdpi.com/2227-9032/10/3/541

Last Updated: Sep 11, 2024