Clinician reference tool — not medical advice. This is a clinical decision-aid intended for healthcare professionals: it gives deterministic suggestions to think with, not a diagnosis or a prescription. If you’re a patient, you’re welcome to look around — but please review anything here with your own doctor; it isn’t a substitute for personalized medical care.
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Electrolytes (sodium, potassium, chloride, bicarbonate)

Wellness panel · specimen: blood

Indicated in specific situations

Also called: electrolytes, lytes, serum electrolytes, Na K Cl, basic metabolic panel

Chart note

Pick Ordered or Not ordered to see the note.

Indicated when

  • Taking a medication that can shift electrolyte levels, such as a diuretic, an ACE inhibitor or ARB, or lithium, where periodic monitoring is standard practice
  • Symptoms of possible volume or electrolyte disturbance, such as vomiting, diarrhea, or significant fluid loss
  • Known or suspected kidney disease, where electrolytes are part of routine monitoring alongside kidney function tests

Not indicated when

  • Routine annual or 'wellness panel' screening in an asymptomatic adult with no relevant medication or symptoms [8]

Why not

In a person with no symptoms, no relevant medication, and no kidney disease, an isolated mild electrolyte deviation is common lab noise rather than a meaningful finding, and can prompt repeat testing without changing management [8, Canadian Society for Medical Laboratory Science / Choosing Wisely Canada 2025].

Better first step

Reserve electrolyte testing for a specific reason: starting or adjusting a medication that affects electrolytes, symptoms of volume or electrolyte disturbance, or known kidney disease, rather than including it in every annual panel by default.

Typical ND rationale

An ND may include electrolytes in a wellness panel, reasoning that sodium, potassium, chloride, and bicarbonate give an early read on hydration, kidney, and adrenal function all at once, so checking them broadly seems like reasonable due diligence.

Where the ND is right

Electrolyte monitoring is genuinely important, and sometimes under-ordered, in anyone taking a diuretic, ACE inhibitor, ARB, or lithium, or with symptoms of fluid loss or known kidney disease; checking it in those situations is standard, appropriate practice. No validated situation for including it in a routine annual panel with no such reason was identified in this session.

Ontario coverage & CONO orderability

OHIP status
insured
Sodium (L226), potassium (L204), chloride (L053), and CO2 content/bicarbonate (L061) are each listed by name in the 2026 Schedule of Benefits for Laboratory Services, insured when ordered by a physician, midwife, or NP who has clinically assessed the patient. ND-ordered testing is not insured and is billed privately (Reg. 552 s.22(1); SOB-LS 2026 preamble).
CONO orderable
Yes — CONO list #114, #100, #39, #36
CONO list item 114, blood: 'Sodium'; item 100, blood: 'Potassium'; item 39, blood: 'Chloride'; item 36, blood: 'Carbon Dioxide Bicarbonate.'

Linked conditions

Counselling script

“If you're on a medication like a water pill, a blood pressure medication, or lithium, or you've had vomiting, diarrhea, or kidney problems, checking your electrolytes makes real sense, and I'll order that today. Without one of those reasons, electrolytes aren't a useful test to include as routine yearly screening, since a mildly abnormal result in someone who's otherwise well usually doesn't mean anything and just leads to more testing. I'll check it whenever a medication or symptom makes it relevant.”

Revisit if

  • A diuretic, ACE inhibitor, ARB, or lithium is started or its dose changed
  • Vomiting, diarrhea, or other significant fluid loss develops
  • New or worsening kidney disease is identified

References

  1. [1]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkSodium (L226) is listed by name in the 2026 OHIP Schedule of Benefits for Laboratory Services
  2. [2]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkPotassium (L204) is listed by name in the 2026 OHIP Schedule
  3. [3]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkChloride (L053) is listed by name in the 2026 OHIP Schedule
  4. [4]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkCO2 content/bicarbonate (L061) is listed by name in the 2026 OHIP Schedule
  5. [5]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkCommunity lab tests are insured only when ordered under the Schedule by an authorized prescriber
  6. [6]Government of Ontario (e-Laws) (2026). Health Insurance Act, R.R.O. 1990, Reg. 552: General, s. 22 (insured laboratory services). linkA lab test is insured only when ordered by a physician, midwife, or NP who has clinically assessed the patient
  7. [7]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkTests ordered by anyone other than an authorized provider, including NDs, are not insured services
  8. [8]College of Family Physicians of Canada / Choosing Wisely Canada (2026). Family Medicine: Fifteen Tests and Treatments to Question. linkDon't do annual screening blood tests unless directly indicated by the patient's risk profile
Evidence notes

This session could not locate and verify a specific guideline statement establishing recommended electrolyte-monitoring intervals for diuretics, ACE inhibitors/ARBs, or lithium (a PubMed search for a matching guideline returned no results within the session's budget); the claim that monitoring is standard practice in these situations reflects widely accepted clinical and product-monograph practice rather than a guideline quoted and verified in this session, and is flagged here rather than presented as sourced fact.