BloodTestEasy

Sodium 170 mEq/L

= 170 mmol/L in SI units

Critically high (severe hypernatremia)

Values in this range are generally treated as a medical emergency. If this is a current result, seek medical care immediately.

100121125130135146150155160170170
  • Critically low (severe hyponatremia)
  • Severely low
  • Moderately low
  • Mildly low
  • Normal
  • Borderline high
  • Moderately high
  • Severely high
  • Critically high (severe hypernatremia)
Your band
Critically high (severe hypernatremia) · 16–17 mEq/L
Distance from typical range
24 mEq/L above 146
SI units
170 mEq/L = 170 mmol/L

What 170 mEq/L means

A sodium of 170 mEq/L is critically high. Most labs flag values at or above 160 mEq/L as a panic result (some flag from 155), and this level needs emergency evaluation.

Severe hypernatremia means the blood is far too concentrated, drawing water out of brain cells and making them shrink. This can cause profound confusion, seizures, and coma, and levels in this range carry a serious risk of complications, particularly in older or frail adults. Values climbing toward 165–170 mEq/L are among the most extreme a lab can report — they are usually seen with severe dehydration in someone who could not drink, heatstroke, untreated diabetes insipidus, or salt poisoning, and without rapid hospital treatment they carry a high risk of permanent injury. Treatment happens in the hospital: the water deficit is replaced slowly under monitoring, because bringing sodium down too fast can cause brain swelling. Do not wait to see if you feel better.

Most US labs report a normal adult sodium range of about 135 to 145 mEq/L (the convention used by MedlinePlus and Mayo Clinic); some labs use 136 to 145. Critical (panic) cutoffs vary slightly between labs: sodium at or below 120 mEq/L is widely treated as a critical low, and 160 mEq/L and above as a critical high, though some labs flag highs starting at 155.

Common causes

  • Severe dehydration, often in someone who could not drink enough (serious illness, frailty, impaired consciousness)
  • Untreated diabetes insipidus with large water losses in urine
  • Major fluid losses from burns, prolonged fever, heatstroke, or severe diarrhea
  • Uncontrolled diabetes with extreme urination
  • Salt poisoning or improperly mixed hypertonic solutions (rare)
  • Certain medications, including lithium (via diabetes insipidus) combined with poor intake

Symptoms that can go with it

  • Extreme thirst (or, worryingly, absence of thirst despite dehydration)
  • Marked confusion or disorientation
  • Severe drowsiness or difficulty waking
  • Muscle twitching or jerking
  • Seizures
  • Very dry mouth and skin
  • Rapid heartbeat and low blood pressure
  • Loss of consciousness

Sensible next steps

  1. Seek emergency care now — go to the emergency department, or call 911 if the person tested is confused, hard to wake, or seizing.
  2. Do not attempt rapid self-rehydration with large volumes of plain water at this level; correction must be gradual and medically supervised.
  3. Bring the lab report and a full medication list, especially lithium and diuretics.
  4. Expect hospital treatment with carefully calculated fluids and frequent repeat sodium checks.
  5. After recovery, work with your clinician on the underlying cause — untreated diabetes insipidus or inadequate fluid access tends to cause repeat episodes.

Frequently asked questions

Is 170 mEq/L a normal sodium level?

No. 170 mEq/L is critically high; most labs flag sodium at or above 160 mEq/L (some from 155) as a panic value. This needs emergency evaluation.

Is a sodium level of 170 dangerous?

Yes. 170 mEq/L is severe hypernatremia, which can cause confusion, seizures, and coma. Seek emergency care now.

What causes low blood sodium (hyponatremia)?

Low sodium almost always means too much water relative to sodium, not too little salt in the diet. Common causes include thiazide diuretics (water pills), antidepressants such as SSRIs, drinking large amounts of water, vomiting or diarrhea, SIADH (excess antidiuretic hormone from lung, brain, or medication causes), and heart, liver, kidney, thyroid, or adrenal conditions. Very high blood glucose can also dilute the measured sodium. Your clinician uses urine tests and your fluid status to sort out which applies to you.

Can drinking too much water cause low sodium?

Yes. Drinking water faster than your kidneys can excrete it dilutes your blood sodium — this is water intoxication. It is a known risk during endurance events when people drink heavily without eating, in people who drink very large volumes habitually, and when illness or medications limit how much water the kidneys can release. For most healthy people, drinking to thirst is the safest guide; there is no need to force extreme volumes of water.

Does eating too much salt raise my blood sodium level?

Usually not. A salty diet makes you thirsty and makes your body hold water, which raises blood pressure and causes puffiness — but the blood sodium concentration typically stays normal because thirst and the kidneys rebalance it. High blood sodium (hypernatremia) is almost always a shortage of water rather than an excess of dietary salt. That said, a lower-salt diet is still worthwhile for blood pressure and heart health, which is a separate issue from this test result.

Should I go to the ER for a sodium of 170 mEq/L?

Yes. 170 mEq/L is a critical high value — go to the emergency department now, and call 911 if there is marked confusion, difficulty waking, or a seizure.

Why is my sodium low if I eat plenty of salt?

Because blood sodium is a concentration, not a measure of salt intake. Low sodium nearly always means your body is holding on to extra water that dilutes the sodium — from medications, hormones like ADH, drinking large volumes, or conditions such as heart, liver, or kidney disease. Adding more salt to your food rarely fixes it and can be harmful in some of these conditions, so the right move is finding the cause with your clinician rather than changing your diet on your own.

Check a different Sodium value

Related values on your lab report

Sources

Educational information, not medical advice. Reference ranges vary between labs — always compare with the range printed on your own report and discuss results with your doctor. Full disclaimer