A free, beginner-friendly guide to common normal lab values for nursing students, medical students, allied health learners, and anyone reviewing core clinical lab ranges.
Learning normal lab values is one of the fastest ways to build clinical confidence. Whether you are studying for nursing school exams, TEAS, NCLEX-style review, medical terminology, or general healthcare coursework, knowing normal ranges helps you recognize when a patient result is low, high, or potentially dangerous.
This page gives you a practical lab values cheat sheet with common ranges, short explanations, and key terms like hyperkalemia, hyponatremia, and leukocytosis. The goal is not just memorization. The goal is understanding.
| Lab | Normal Range | Why it matters |
|---|---|---|
| Sodium (Na+) | 135 to 145 mEq/L | Important for fluid balance, nerve function, and muscle function. |
| Potassium (K+) | 3.5 to 5.0 mEq/L | Critical for cardiac rhythm and muscle contraction. |
| Calcium (Ca2+) | 8.5 to 10.5 mg/dL | Supports bones, nerves, and muscle contraction. |
| Magnesium (Mg2+) | 1.5 to 2.5 mEq/L | Helps regulate neuromuscular and cardiac function. |
| Chloride (Cl-) | 96 to 106 mEq/L | Helps maintain acid-base balance and hydration. |
Hyperkalemia means high potassium in the blood. Hypokalemia means low potassium in the blood. Because potassium affects the heart, abnormal potassium levels are especially important to understand.
| Lab | Normal Range | Why it matters |
|---|---|---|
| WBC | 4,000 to 11,000 cells/mcL | Often used to help assess infection or inflammation. |
| Hemoglobin | Male: 13.5 to 17.5 g/dL Female: 12.0 to 15.5 g/dL |
Helps evaluate oxygen-carrying capacity and anemia. |
| Hematocrit | Male: 41% to 53% Female: 36% to 46% |
Represents the percentage of blood made up of red blood cells. |
| Platelets | 150,000 to 450,000/mcL | Important for blood clotting. |
Leukocytosis means an elevated white blood cell count. Anemia is often associated with low hemoglobin or low hematocrit.
| Lab | Normal Range | Why it matters |
|---|---|---|
| Glucose | 70 to 99 mg/dL fasting | Used to help assess blood sugar control. |
| BUN | 7 to 20 mg/dL | Used in kidney function assessment. |
| Creatinine | 0.6 to 1.3 mg/dL | Another key marker of kidney function. |
| CO2 / Bicarbonate | 22 to 28 mEq/L | Helps reflect acid-base status. |
Medical terminology becomes easier when you break the words down instead of trying to memorize them all at once.
This is one reason MedSkillBuilder focuses on understanding prefixes, suffixes, and core clinical concepts together.
Reading lab values is helpful, but testing yourself is even better. Use the quiz below to reinforce common ranges and build retention.
Start with sodium, potassium, calcium, glucose, white blood cells, hemoglobin, and platelets. These are commonly tested and often discussed in early healthcare training.
Potassium plays a major role in cardiac rhythm and muscle function. Abnormal potassium levels can be serious, which is why learners often study hyperkalemia and hypokalemia early.
Start with a cheat sheet, then use quizzes and short repetition sessions. Pairing lab values with medical terminology also helps many students understand the meaning behind the numbers.
Note: Lab reference ranges can vary slightly by source, lab, and clinical setting. This page is for educational review and study support only, not for diagnosis or treatment decisions.