Ajax Harwood Clinic
Why am I tired?
Fatigue is one of the most common presenting complaints in primary care, and the differential is broad: sleep disorders, mood disorders, medication effects, substance use, endocrine and metabolic disease, anemia and nutrient deficiency, chronic organ disease, malignancy, and post-viral or functional syndromes. The base rate of serious underlying somatic pathology is low, and the diagnostic yield of unfocused blood testing is correspondingly low, so history and exam should drive test selection rather than a broad panel. This page routes patients to the specific 'should I be tested?' and existing AHC tools rather than duplicating them.
Common causes
Insufficient or poor-quality sleep(more →)
Clues: Short sleep duration, irregular schedule, screens/caffeine/alcohol near bedtime, snoring partner denies apnea, symptoms improve on days off or vacation
Next step: Sleep history and sleep diary; consider referral if insomnia criteria are met
Obstructive sleep apnea(more →)
Clues: Loud snoring, witnessed apneas, morning headache, unrefreshing sleep despite adequate hours, obesity, large neck circumference, resistant hypertension
Next step: STOP-Bang screening; refer for sleep study if score suggests intermediate/high risk
Depression or anxiety(more →)
Clues: Low mood, anhedonia, poor concentration, early morning waking, appetite change, worry out of proportion to circumstances
Next step: Mood and anxiety screen as part of history
Medication effect
Clues: Temporal relationship to a new drug: beta-blockers, antihistamines (especially first-generation), opioids, benzodiazepines, SSRIs/SNRIs, some antihypertensives
Next step: Medication review; consider dose, timing or agent change if a culprit is identified
Alcohol or other substance use
Clues: Quantity/frequency on direct questioning, sleep fragmentation from alcohol, withdrawal symptoms, cannabis or sedative use
Next step: Non-judgmental substance use history
Shift work(more →)
Clues: Rotating or night shifts, symptoms track with schedule, circadian misalignment
Next step: Sleep hygiene counselling tailored to shift pattern; treat as a sleep problem
Iron deficiency, with or without anemia(more →)
Clues: Heavy menstrual bleeding, restrictive diet, pregnancy, GI blood loss, pica, restless legs; can cause fatigue before hemoglobin falls
Next step: Ferritin
Hypothyroidism(more →)
Clues: Cold intolerance, weight gain, constipation, dry skin, bradycardia, goitre, personal or family history of thyroid or autoimmune disease
Next step: TSH
Diabetes or poor glycemic control(more →)
Clues: Polyuria, polydipsia, unintentional weight loss, blurred vision, recurrent infections, risk factors (obesity, family history, prior gestational diabetes)
Next step: A1c or fasting glucose
B12 deficiency(more →)
Clues: Vegan/vegetarian or otherwise limited intake, older age, metformin or PPI use, prior bariatric surgery, paresthesias, gait or balance change
Next step: B12
Celiac disease(more →)
Clues: GI symptoms (diarrhea, bloating, weight loss), iron or other nutrient deficiency without an obvious cause, dermatitis herpetiformis, first-degree relative with celiac disease
Next step: Celiac serology (tTG-IgA + total IgA) if any of the above, not as a routine addition
Pregnancy
Clues: Missed period, breast tenderness, nausea, in a person of reproductive age
Next step: Pregnancy test when clinically relevant
Post-viral fatigue or long COVID(more →)
Clues: Onset after a documented infection, especially with exertional worsening, brain fog, or autonomic symptoms
Next step: Document the index infection and course; supportive management and pacing
ME/CFS (post-exertional malaise)(more →)
Clues: Fatigue lasting more than 6 months with post-exertional malaise, unrefreshing sleep, and cognitive or orthostatic symptoms, after excluding other causes
Next step: Apply diagnostic criteria; this is a clinical diagnosis of exclusion
Menopause / perimenopause(more →)
Clues: Irregular or absent periods, vasomotor symptoms, sleep disruption from night sweats, age-appropriate
Next step: Clinical diagnosis in a woman over about 45 with typical symptoms; labs usually not needed
Heart, lung, kidney or liver disease
Clues: Dyspnea on exertion, orthopnea, edema, known heart failure/COPD/CKD/cirrhosis, abnormal exam findings
Next step: Directed exam and testing (e.g. creatinine/eGFR, liver enzymes, BNP if indicated) based on findings, not routine screening
Malignancy
Clues: Unintentional weight loss, night sweats, new lymphadenopathy, bleeding, persistent localized pain, age-appropriate risk
Next step: Targeted work-up based on the specific red flag, not a tumour marker panel
History & exam
- • Onset, duration, pattern (constant vs. fluctuating), and relationship to exertion, sleep, mood and work schedule
- • Full medication and substance use review, including over-the-counter and supplement use
- • Sleep history: duration, quality, snoring, witnessed apneas, restless legs
- • Mood and anxiety screen
- • Menstrual, reproductive and menopausal history
- • Diet, including restrictive or vegan/vegetarian patterns, and GI symptoms
- • Red-flag review of systems: weight loss, fever, night sweats, bleeding, dyspnea, chest pain, focal neurologic symptoms
- • Vitals including weight trend and orthostatic blood pressure if indicated
- • General exam: pallor, lymphadenopathy, thyroid, cardiac and respiratory exam, abdominal exam, edema, signs of chronic liver or kidney disease
Initial labs
- • Complete blood count (CBC) — Screens for anemia and hints at underlying causes (microcytic vs. macrocytic) and for infection or hematologic disease
- • Ferritin — Iron deficiency causes fatigue before anemia develops; ferritin is the test of choice
- • TSH (thyroid stimulating hormone) — TSH alone is the appropriate first test for thyroid dysfunction in most situations
- • HbA1c and fasting glucose (diabetes screening) — Screens for diabetes, which can present with fatigue, especially with other suggestive symptoms
- • Electrolytes (sodium, potassium, chloride, bicarbonate) — Detects metabolic disturbance that can cause or contribute to fatigue
- • Kidney function (creatinine/eGFR, BUN, urine albumin-to-creatinine ratio) — Detects chronic kidney disease, which is often asymptomatic until advanced
- • Celiac serology (tTG-IgA + total IgA) — Add if GI symptoms, unexplained nutrient deficiency, or a first-degree relative with celiac disease; not a routine addition for isolated fatigue
Not routinely indicated
- • Diurnal salivary cortisol panel (4-point / "adrenal stress") — No validated use for fatigue; 'adrenal fatigue' is not recognized by any endocrinology society
- • Vitamin D, 25-hydroxy (25-OH vitamin D) — Routine testing in an unselected patient with fatigue is not supported; test only with a specific risk factor or clinical indication
- • Annual bloodwork / wellness panel (executive health screen) — Broad 'wellness' or executive-health panels in asymptomatic or non-specifically fatigued patients increase false positives without improving outcomes
Red flags
- • Unintentional weight loss
- • Fever or night sweats
- • New or unexplained lymphadenopathy
- • Unexplained bleeding (GI, gynecologic, or other)
- • Focal neurologic signs
- • Dyspnea or chest pain
- • New fatigue after age 50 with other systemic symptoms
- • Rapidly progressive or severe fatigue disproportionate to activity
When labs are normal
Most patients presenting with unexplained fatigue have normal initial blood work: in one Dutch primary-care trial, only 8% of patients had a somatic illness detectable by blood testing. A normal panel is expected and reassuring, not a sign that testing was inadequate or that something was missed. Expanding the test set (extra hormone panels, food-sensitivity panels, broader autoimmune or toxicology testing) increases false positives more than it increases true diagnoses. When initial labs are normal, focus returns to sleep, mood, medications, alcohol, and lifestyle factors, with a clear plan to revisit if the picture changes or red flags develop. Set a specific follow-up interval (e.g. 4-6 weeks) rather than open-ended reassurance.
Chart snippets (OSCAR-safe plain text)
Initial visit
Presenting concern: fatigue. History: sleep pattern, mood, medications, alcohol/substance use, menstrual and dietary history reviewed. Red flags (weight loss, fever, night sweats, lymphadenopathy, bleeding, focal neuro signs, dyspnea) absent. Exam: unremarkable, thyroid and cardiorespiratory exam normal. Assessment: fatigue, likely multifactorial; no red flags identified. Plan: CBC, ferritin, TSH, A1c or fasting glucose, electrolytes, creatinine/eGFR ordered. Celiac serology added if GI symptoms present. Patient given info page: https://tired.ajaxharwoodclinic.com/patient Revisit if: symptoms worsen, red flags develop, or fatigue persists beyond 4-6 weeks despite normal work-up.
Labs normal — follow-up
Fatigue work-up reviewed: CBC, ferritin, TSH, A1c/glucose, electrolytes and creatinine/eGFR normal. Discussed that most fatigue work-ups are normal and this is reassuring, not inconclusive; Ref: Koch et al, BJGP 2009. Assessment: fatigue without identified organic cause on initial testing. Plan: focus on sleep, mood, alcohol, and medication review; consider sleep apnea screening (STOP-Bang) and mood screen if not already done. Discussed avoiding broad add-on panels (adrenal/cortisol, routine vitamin D, wellness panels) given low yield; Ref: Morgan et al, Can Fam Physician 2015. Revisit if: symptoms worsen, new red flags develop, or no improvement by next visit.
References
- 1. British Journal of General Practice. Ordering blood tests for patients with unexplained fatigue in general practice: what does it yield? Results of the VAMPIRE trial (2009)Diagnostic yield of blood testing in unexplained fatigue is low; supports restricting the number of tests ordered
- 2. Canadian Family Physician. Rational test ordering in family medicine (2015)Ordering tests mainly to reassure a low-risk patient does little to reduce anxiety; supports serial rather than parallel testing
- 3. Sleep and Breathing. Validation of the STOP-Bang questionnaire for screening of obstructive sleep apnea in the general population and commercial drivers: a systematic review and meta-analysis (2021)STOP-Bang is a validated screening tool for obstructive sleep apnea in the general population
- 4. Royal College of Physicians (Clinical Medicine). Iron deficiency without anaemia: a diagnosis that matters (2021)Iron deficiency without anemia is common and can cause fatigue; ferritin is the test of choice
- 5. Ontario Association of Medical Laboratories (OAML). Guideline for the Use of Laboratory Tests to Detect Thyroid Dysfunction (CLP 015) (2007)— older guidelineTSH alone is the appropriate initial test for thyroid dysfunction in most situations
- 6. National Institute for Health and Care Excellence (NICE). Vitamin B12 deficiency in over 16s: diagnosis and management (NG239) (2024)Testing pathway for suspected B12 deficiency based on symptoms and risk factors
- 7. American College of Gastroenterology. American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease (2023)tTG-IgA serology as the recommended initial screening test for celiac disease
- 8. BMC Endocrine Disorders. Adrenal fatigue does not exist: a systematic review (2016)— older guideline'Adrenal fatigue' is not recognized by any endocrinology society; no validated test detects it
- 9. College of Family Physicians of Canada / Choosing Wisely Canada. Family Medicine: Fifteen Tests and Treatments to Question (2026)Vitamin D testing in average-risk, asymptomatic adults is not routinely recommended
- 10. College of Family Physicians of Canada / Choosing Wisely Canada. Family Medicine: Fifteen Tests and Treatments to Question (2026)No routine screening blood tests (broad wellness panels) in asymptomatic patients
- 11. Diabetes Canada. Diabetes Canada Clinical Practice Guidelines: Screening for Diabetes in Adults (2018)A1c or fasting glucose as the standard screening test for diabetes
- 12. Kidney Disease: Improving Global Outcomes (KDIGO). Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease: known knowns and known unknowns (2024)Creatinine/eGFR is the standard test for detecting chronic kidney disease, which is often asymptomatic
Evidence notes
The brief asked specifically for a NICE CKS 'Tiredness/fatigue in adults' citation; that page is geo-restricted to UK IPs (confirmed: direct fetch returns 'CKS is only available in the UK', and no usable Wayback Machine snapshot exists either — all archived captures are redirects or 403s). It was not used. In its place this page relies on (a) the Koch 2009 BJGP cohort for the low-yield-of-testing message, which is the specific empirical claim the brief wanted NICE CKS for, and (b) the existing verified references already attached to cbc/ferritin/tsh/a1c-glucose/electrolytes/kidney-function/celiac-serology in data/tests.json for which tests belong in the initial panel. A CMAJ 2006 review ('Fatigue: a practical approach to diagnosis in primary care', Cornuz et al.) was located but is paywalled with no accessible abstract or open full text found via PubMed, Crossref, Europe PMC, or Wayback Machine; it was replaced with Morgan et al., Can Fam Physician 2015 ('Rational test ordering in family medicine'), which is Canadian, open access, and covers the same over-testing/reassurance-testing point plus explicitly cites fatigue investigation guidelines as an example. PHQ-2/PHQ-9 and a discrete depression-screening source were not added in this pass; the depression. tool is the routing target and presumably already carries that evidence, so no new source was fetched here to stay within budget — flag for the reviewer if a direct citation is wanted on this page itself. Physiology statements connecting specific medication classes (beta-blockers, antihistamines, opioids, SSRIs) to fatigue are common clinical knowledge and were not separately sourced. Diabetes Canada 2018 guideline is now 8 years old; current 2023 update exists and should be checked when the diabetes. tool is next revised, though the core A1c/fasting-glucose screening recommendation has not changed materially.
General clinical reference for Ajax Harwood Clinic. Not medical advice, and not a substitute for individualized clinical assessment.