Lab values come up across the NCLEX, especially in Reduction of Risk Potential and Pharmacological Therapies. You’ll often have to decide whether a result is normal, whether it needs to be reported and what to do next. Here are the common adult ranges taught in nursing programs, followed by free practice questions.
Reference ranges vary by laboratory and textbook. In practice, always use your facility’s ranges.
Electrolytes
Lab
Typical adult range
Sodium (Na)
135 to 145 mEq/L
Potassium (K)
3.5 to 5.0 mEq/L
Calcium (total)
9.0 to 10.5 mg/dL
Magnesium
1.3 to 2.1 mEq/L
Chloride
98 to 106 mEq/L
Glucose and kidney function
Lab
Typical adult range
Fasting blood glucose
70 to 100 mg/dL
Hemoglobin A1C
Below 5.7% (normal)
BUN
10 to 20 mg/dL
Creatinine
0.6 to 1.2 mg/dL
Blood counts
Lab
Typical adult range
WBC
5,000 to 10,000/mm³
Hemoglobin
About 12 to 16 g/dL (women), 14 to 18 g/dL (men)
Hematocrit
About 37% to 47% (women), 42% to 52% (men)
Platelets
150,000 to 400,000/mm³
Clotting
Lab
Typical value
INR (not on anticoagulants)
About 0.8 to 1.1
INR (on warfarin, most indications)
Therapeutic range usually 2 to 3
Free lab values practice questions
A client's potassium is 6.2 mEq/L. Which is the nurse's priority?
Answer: APotassium above 5.0 mEq/L is high (hyperkalemia), and 6.2 can cause dangerous heart rhythms. The priority is cardiac monitoring and notifying the provider.
Which is a normal fasting blood glucose?
Answer: BA normal fasting blood glucose is about 70 to 100 mg/dL.
A client on warfarin for atrial fibrillation has an INR of 2.5. What does this mean?
Answer: BFor most indications, the therapeutic INR on warfarin is 2 to 3, so 2.5 is within range.
A client's platelet count is 45,000/mm³. Which precaution is most important?
Answer: CA low platelet count (thrombocytopenia) raises the risk of bleeding. Bleeding precautions, such as a soft toothbrush and electric razor, help prevent injury.
Which sodium level is normal?
Answer: BNormal sodium is about 135 to 145 mEq/L. 128 is low (hyponatremia), and 150 and 160 are high (hypernatremia).
A client's creatinine has risen from 0.9 to 2.4 mg/dL. What does this most likely suggest?
Answer: DCreatinine is cleared by the kidneys, so a rising creatinine suggests the kidneys are filtering less well. Report the change to the provider.
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