Effective Treatment Requires an Accurate Diagnosis

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Introduction

People often use diagnostic terms to describe physical or mental health symptoms.
A diagnosis requires direct assessment by a professional with training to distinguish between conditions with similar symptoms.
A diagnosis is a process, not a label.

Symptoms versus Diagnosis

It is common to hear people say they are “allergic” to a food when they mean they are “intolerant” to it. Diagnosis of food allergy requires being assessed by a medical doctor (Allergist) who can distinguish IgE-mediated allergies, non-IgE-mediated allergies, and food intolerance.
  • Food allergies may be IgE-mediated sensitivity to a specific food, such as peanuts, or sesame that may cause anaphylaxis, breathing difficulties, hives or rashes, or gastrointestinal symptoms, such as in Oral Allergy Syndrome (OAS), also called pollen-food syndrome, which may involve itching and tingling in the mouth or throat in response to raw fruits or raw vegetables [1].
  • Food allergies may also be non-IgE mediated and include celiac disease (IgA mediated), food protein-induced enterocolitis syndrome (FPIES), food protein-induced enteropathy (FPE), and food protein-induced allergic proctocolitis (FPIAP) [1].
  • Food intolerances, such as lactose intolerance, are a digestive system response that may cause symptoms such as abdominal pain, bloating, flatulence (gas), or diarrhea, and that does not involve the immune system.
It’s common to hear people say they are “depressed” when they feel sad or down at that time, or “anxious” when they feel stressed. These are very different from a clinical diagnosis of “depression,” i.e., Major Depressive Disorder (MDD) based on the Diagnostic and Statistical Manual of Mental Disorders (DSM), which defines it as a person experiencing five or more specific symptoms over the same 2-week period [2]. A diagnosis of Generalized Anxiety Disorder (GAD) requires 3 or more of 6 specific symptoms to be present more days than not during the last 6 months [2]. 

What is Diagnosis and How is it Made?

Diagnosis is an evaluative process performed directly by a qualified healthcare professional trained to distinguish a specific condition from others with similar symptoms (differential diagnosis), which is used to determine the nature of a disease, disorder, or health condition by a clinician [1] [2] [3].
1. A diagnosis is made based on multiple clinical evaluations required to differentiate between several conditions that have similar symptoms.
  • For example, symptoms of abdominal pain or bloating could be due to celiac disease, an h. pylori infection, or perhaps even Inflammatory Bowel Disease (IBD).
  • Symptoms of anxiety might be due to General Anxiety Disorder (GAD), post-traumatic stress disorder (PTSD), or Panic Disorder.

Multiple diagnostic assessments by a qualified healthcare professional need to be performed to be able to make an accurate diagnosis.

2. A diagnosis must be made based on direct interaction between the provider and the patient [4], either where

  • The patient and provider are in the same room, or
  • synchronously (real-time) video or audio, where clinically appropriate for the specific diagnosis

A diagnosis cannot be made on the basis of reported symptoms, nor can it be made by listening to a podcast or reading a book, regardless of the speaker’s or author’s credentials. A valid diagnosis requires (a) direct interaction between a qualified clinician and the individual being assessed within a (b) formal provider-patient relationship—either (c) in person or virtually, where clinically appropriate [4].

Who is Qualified to Make a Diagnosis?

Physical Health

A medical doctor, including a General Practitioner (GP) or a specialist such as a Gastroenterologist, can diagnose, as can a Nurse Practitioner. For example,

  • A diagnosis of Irritable Bowel Disorder (IBS) can be made based on the Rome Criteria, after ruling out underlying physical causes, such as celiac disease, an h.pylori infection, or, in some cases, Inflammatory Bowel Disease (IBD) [8] [9].
  • A diagnosis of celiac disease can be made using an IgAtTg blood test as a screening tool, confirmed by a small intestinal biopsy [10].
  • A diagnosis of food allergies can be made by an medical doctor (Allergist) based on the presence of IgE antibodies or specific non-IgE antibodies (e.g., IgAttg). An IgG antibody test panel available through many naturopaths or purchased directly from a lab does not diagnose food allergies.

Physical health diagnoses are made based on meeting specific criteria outlined in the International Statistical Classification of Diseases and Related Health Problems (ICD) [3].

As a Registered Dietitian, I do not diagnose. I provide treatment based on a diagnosis.

Mental Health

A medical doctor, including a Psychiatrist and General Practitioner (GP), or a Registered Psychologist (R. Psych), can diagnose mental health conditions based on clinical assessment, which may include structured interviews and administering Standardized Rating Scales.

  • Structured Interviews using a specific script, such as the Structured Clinical Interview for DSM (SCID)
  • Behavioral Observation and Functional Assessment
  • Standardized Rating Scales, such as screens for Generalized Anxiety Disorder, Beck Anxiety Inventory (BAI), Hamilton Anxiety Rating Scale (HAM-A), or the Penn State Worry Questionnaire (PSWQ)
  • Cognitive testing, when applicable

Mental health diagnoses are made based on meeting specific criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) [2].

Registered Clinical Counsellors (RCC) do not diagnose, but can provide treatment.

Is a Diagnosis Always Necessary?

Once a person meets a diagnostic criterion and has been diagnosed with a specific condition, a Registered Dietitian is trained and qualified to provide dietary treatment, but a diagnosis is not always required to make dietary or behavioural changes.

Wanting to improve lab test results that are within lab values but not optimal, or to normalize abnormal lab results that do not meet the criteria for clinical diagnosis, is a good reason to get a Dietitian’s help. That said, one still needs to have regular diagnostic lab tests or to monitor parameters such as blood sugar or blood pressure at home.

Similarly, in mental health, a person may see a Registered Clinical Counsellor (RCC) to better manage stress or to improve how they think about themselves or circumstances, but this is not a substitute for assessment and diagnosis by a Registered Psychologist (R. Psych), or Psychiatrist.

Why Diagnosis Matters?

A person who thinks they have IBS may unnecessarily avoid a whole range of foods based on what they’ve assumed, and this may contribute to inadequate dietary intake. More significantly, a person who has been told they have IBS based on symptoms might actually test positive as having celiac disease if they had received adequate testing. In the absence of proper assessment and diagnosis, damage is being caused to this person’s small intestine. Effective treatment requires a correct diagnosis.

Likewise, someone who is told or believes that they have a specific mental health diagnosis based on second-hand information in the absence of proper assessment should be evaluated by a healthcare professional who can make a differential diagnosis after thorough assessment. Effective treatment requires a correct diagnosis.

Final Thoughts

While symptoms may improve with dietary or behavioural modifications, the very same symptoms are often present in multiple health conditions. Treating symptoms without proper assessment and diagnosis is inadequate at best and could potentially delay proper diagnosis and treatment.
Effective treatment requires assessment and diagnosis by a qualified healthcare professional who is trained to differentiate between conditions with similar symptoms.

More Info

Learn about me and how I can assist in the process of getting diagnosed with routine and digestive disorders, and about the various services that I offer.

To your good health.

Joy

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References

  1. Gargano D, Appanna R, Santonicola A, De Bartolomeis F, Stellato C, Cianferoni A, Casolaro V, Iovino P. Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns. Nutrients. 2021; 13(5):1638. https://doi.org/10.3390/nu13051638 Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545237/
  2. American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.). https://doi.org/10.1176/appi.books.9780890425787
  3. Canadian Institute for Health Information. (2024). The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada (ICD-10-CA). https://www.cihi.ca/en/icd-10-ca
  4. Federation of Medical Regulatory Authorities of Canada. (2022). Framework on Virtual Care. https://fmrac.ca/wp-content/uploads/2022/07/FMRAC-Framework-on-Virtual-Care.pdf
  5. Canada Health Act. Revised Statutes of Canada 1985, c. C-6. Justice Laws Website, Government of Canada, laws-lois.justice.gc.ca/eng/acts/c-6/.
  6. Generoso MB, Sanches M. Classifications and the Diagnostic Process in Psychiatry. In: Sanches M, Soares JC, eds. Fundamentals of Clinical Psychiatry: A Practical Handbook. Cambridge University Press; 2025:19-26.
  7. The Public Health Agency of Canada, Glossary of terms: A shared understanding of the common terms used to describe psychological trauma, version 3.0, November 2023, https://www.canada.ca/en/public-health/services/reports-publications/health-promotion-chronic-disease-prevention-canada-research-policy-practice/vol-43-no-10-11-2023/glossary-common-terms-psychological-trauma-version-3-0.html
  8. International Foundation for Gastrointestinal Disorders (IFFGD), Diagnosing IBS, https://aboutibs.org/what-is-ibs/diagnosis-of-ibs/
  9. Nemakayala DR, Cash BD. Excluding inflammatory bowel disease in the irritable bowel syndrome patient: how far to go? Curr Opin Gastroenterol. 2019 Jan;35(1):58-62. doi: 10.1097/MOG.0000000000000493. Erratum in: Curr Opin Gastroenterol. 2019 Jul;35(4):394. doi: 10.1097/MOG.0000000000000556. PMID: 30407259.
  10. Celiac Canada, State of Celiac – 20 years after the first survey, what’s changed, May 3, 2024, https://e.issuu.com/embed.html
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