Published: 27 Oct 2024

Blood Test Reference Ranges for Adults

Understanding normal laboratory reference ranges is crucial for interpreting patient test results. These ranges vary based on factors such as age, gender, and laboratory methodology.

Common Lab Tests and Reference Ranges:

1. Blood Count Tests:

* White Blood Cell (WBC) Count: 4,500-11,000 cells/mcL
* Red Blood Cell (RBC) Count:
* Men: 4.7-6.1 million cells/mcL
* Women: 4.2-5.4 million cells/mcL
* Hemoglobin (Hb):
* Men: 13.8-17.2 g/dL
* Women: 12.1-15.1 g/dL
* Hematocrit (Hct):
* Men: 41-50%
* Women: 36-44%
* Platelet Count: 150,000-450,000/mcL

2. Electrolytes and Minerals:

* Sodium (Na): 135-145 mEq/L
* Potassium (K): 3.5-5.0 mEq/L
* Chloride (Cl): 96-106 mEq/L
* Calcium (Ca): 8.5-10.5 mg/dL
* Magnesium (Mg): 1.7-2.2 mg/dL
* Phosphate: 2.5-4.5 mg/dL

3. Renal Function Tests:

* Blood Urea Nitrogen (BUN): 7-20 mg/dL
* Creatinine:
* Men: 0.6-1.2 mg/dL
* Women: 0.5-1.1 mg/dL
* Glomerular Filtration Rate (GFR): 90-120 mL/min (age-dependent, generally decreases with age)

4. Liver Function Tests:

* Alanine Aminotransferase (ALT): 7-56 U/L
* Aspartate Aminotransferase (AST): 10-40 U/L
* Alkaline Phosphatase (ALP): 44-147 U/L
* Bilirubin: 0.1-1.2 mg/dL
* Albumin: 3.5-5.0 g/dL

5. Thyroid Function Tests:

* Thyroid Stimulating Hormone (TSH): 0.4-4.0 mIU/L
* Free T4 (Thyroxine): 0.8-1.8 ng/dL
* Free T3 (Triiodothyronine): 2.3-4.1 pg/mL

6. Lipid Panel:

* Total Cholesterol: Less than 200 mg/dL
* LDL Cholesterol: Less than 100 mg/dL (optimal)
* HDL Cholesterol:
* Men: Greater than 40 mg/dL
* Women: Greater than 50 mg/dL
* Triglycerides: Less than 150 mg/dL

7. Glucose and Diabetes Markers:

* Fasting Blood Glucose: 70-99 mg/dL (fasting)
* Hemoglobin A1c (HbA1c): Less than 5.7% (for non-diabetics)

8. Inflammation Markers:

* C-Reactive Protein (CRP): Less than 3.0 mg/L (high-sensitivity CRP may vary)
* Erythrocyte Sedimentation Rate (ESR):
* Men: 0-15 mm/hr
* Women: 0-20 mm/hr

Tips for Using Reference Ranges:

* Always refer to the specific laboratory's reference ranges.
* Consider factors like age, gender, and health status.
* Certain conditions may warrant adjusted ranges.
* Interpret results in the context of patient symptoms and history.
* Reference ranges are guidelines, but clinical correlation is essential.