Introduction to Electrolyte Labs
Electrolytes are minerals found in blood and body fluids that carry electrical charges. They help the body regulate chemical reactions and maintain the balance between fluids inside and outside the cell.
Electrolyte lab values help determine whether your client is dehydrated or needs rehydrating.
If one or more of these electrolytes become imbalanced in the body, it can cause serious problems. Electrolyte imbalances can be dangerous if left untreated, and can result in shock or cardiac arrhythmia. It’s a key nursing responsibility to be familiar with electrolyte values.
When electrolytes are in homeostasis (maintained at the normal values), the more efficient the kidneys are at filtering out toxins. But if a client has chronic kidney disease and doesn’t get enough electrolytes, it can make the kidneys less efficient at filtering out waste products from the body. One of the functions of healthy kidneys is to filter blood and remove waste products such as urea from the body.
The six electrolytes include:
- Sodium (Na+)
- Potassium (K+)
- Chloride (Cl-)
- Calcium (Ca2+)
- Magnesium (Mg2+)
- Phosphate (P)
preparing
to take the
NCLEX?
Normal Electrolyte Lab Values
Sodium: 135 to 145 mmol/L
Priority, Pumps the Heart
Potassium: 3.5 to 5.0 mmol/L
Maintains blood pressure, blood volume, and pH balance
Calcium: 8.5 to 10.2 mg/dL (in adults)
Keeps the 3 Bs Strong: Bone, Blood (clotting), and Beats (heart)
Chloride: 97 to 107 mmol/L
Maintains blood pressure, blood volume, and pH balance
Magnesium: 1.3 to 2.1 mg/dL
Mellows the muscles
Phosphate: 3.0 to 4.5 mg/dL
When Ca is high = Phosphate is low – and when Ca is low = Phosphate is high
Electrolyte Imbalances (with Lab Values & Memory Tricks)
When a client’s electrolytes are imbalanced, it affects the body’s processes. For example, if the client has low potassium levels, it can cause muscle weakness and heart arrhythmias.
These imbalanced levels of electrolytes result in hyper or hypo conditions, such as hypercalcemia (too much calcium) and hyponatremia (too little sodium).
Electrolytes | High (Hyper) | Low (Hypo) |
Potassium K+ | Hyperkalemia (over 5.0) | Hypokalemia (below 3.0) |
Sodium Na+ | Hypernatremia (over 145) | Hyponatremia (below 135) |
Chloride Cl- | Hyperchloremia (over 107) | Hypochloremia (below 97) |
Magnesium Mg+ | Hypermagnesemia (over 2.1) | Hypomagnesemia (below 1.3) |
Calcium Ca | Hypercalcemia (over 10.5) | Hypocalcemia (below 9.0) |
Phosphate P | Hyperphosphatemia (over 4.5) | Hypophosphatemia (below 3.0) |
Hyponatremia Pathophysiology
Hyponatremia is an electrolyte imbalance (below 135 Na+) caused by water intoxication. Water intoxication occurs when someone drinks so much water that it dilutes the sodium in the blood and overwhelms the kidney’s compensation mechanism).
It can also be caused by a syndrome of inappropriate antidiuretic hormone secretion (SIADH). SIADH is associated with conditions such as pneumonia, brain diseases, cancer, thyroid problems, and taking some medications.
Hyponatremia Causes
- Sweating
- Excess water intake
- Running in extreme heat
- SIADH
- Vomiting and diarrhea
- Diuretics and Diuresis
- Diets low in salt
- Low aldosterone
Hyponatremia Signs and Symptoms
- Brain is low and slow
- Headache = Cerebral edema
- Mental status changes
- Seizures and coma
- Muscular = low and slow
- Fatigue and muscle cramps
- Respiratory = low and slow
- Respiratory arrest
Hyponatremia Nursing Interventions
- Monitor fluid volume status.
- Administer IV fluids and medications as ordered.
- Encourage eating foods and fluids with sodium (salt).
- Assess weight and skin turgor (to identify dehydration).
- Practice seizure precautions.
Hypernatremia Pathophysiology
Hypernatremia (over 145 Na+) occurs when there is too little water, instead of too much sodium, in the body. This water loss can result from illness with vomiting or diarrhea, excessive sweating from exercise or fever, or from drinking fluid that has too high concentrations of salt.
Hypernatremia Causes
- Low ADH (antidiuretic hormone)
- DI: Diabetes Insipidus
- Rapid respirations
- Watery diarrhea
- Loss of thirst
Hypernatremia Signs and Symptoms
- Body = big and bloated
- Edema (swollen body)
- Flushed “red & rosey” skin
- Increased muscle tone
- Swollen dry tongue
- Nausea & Vomiting
Chronic Kidney Disease
The kidneys are responsible for filtering waste products out of the blood and into urine. They also help to maintain the balance of electrolytes in the body. If the kidneys become damaged, they can no longer perform these functions effectively, which can lead to chronic renal failure and other complications.
When a client has Chronic Kidney Disease (CKD), the kidneys can’t get rid of electrolytes.
Chronic kidney disease can lead to high blood pressure and associated heart disease and stroke risks. It also increases the risk of developing osteoporosis and muscle weakness due to low potassium levels, which are associated with increased fall risk among older adults.

During my exam, I could literally see and hear him going over different areas as I was answering my questions.
This past Friday I retook my Maternity Hesi and this time, I decided for my last week of Holiday break to just watch all of his OB videos. I am proud to say that with Mike’s help I received a score of 928 on my Maternity Hesi!

Electrolyte Labs Conclusion
Electrolytes are an essential part of how the body functions. They affect everything from hydration to the heart. They also help the health care provider (HCP) to be able to diagnose a wide variety of medical conditions. A nursing responsibility is understanding electrolytes and how they affect the body, along with normal lab values and interventions that can impact client care.
Sources
https://my.clevelandclinic.org/health/diagnostics/22358-electrolyte-panel
https://my.clevelandclinic.org/health/symptoms/24019-electrolyte-imbalance
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129840/