Blood, Sweat, No Tears: A Guide to Better Understanding Your Lab Results 

Ever stared at your lab results and felt like you were trying to crack a secret code? You're not alone! Understanding your blood work can help you stay proactive about your health. Below is a quick reference guide to normal ranges for common lab tests, along with potential reasons why values may be high or low. Keep in mind that slight variations may exist between labs and what may be considered "abnormal" by the lab could be YOUR normal. Needles to say, always discuss your results with your provider. 

 Complete Blood Count (CBC) with Differential 

• White Blood Cells (WBC): 4,000–11,000/µL 

• High: Infection, inflammation, leukemia, stress, corticosteroids 

• Low: Viral infections, bone marrow disorders, autoimmune diseases, chemotherapy 

• Red Blood Cells (RBC): 4.7–6.1 million/µL (men), 4.2–5.4 million/µL (women) 

• High: Dehydration, polycythemia vera, lung disease, high altitude 

• Low: Anemia (iron, B12, folate deficiency), kidney disease, blood loss 

• Hemoglobin (Hgb): 13.8–17.2 g/dL (men), 12.1–15.1 g/dL (women) 

• High: Dehydration, lung disease, polycythemia 

• Low: Anemia, bleeding, kidney disease 

• Hematocrit (Hct): 40–52% (men), 36–47% (women) 

• High: Dehydration, polycythemia, COPD 

• Low: Anemia, overhydration, chronic disease 

• Platelets: 150,000–450,000/µL 

• High: Infection, inflammation, cancer, iron deficiency 

• Low: Bone marrow disorders, liver disease, autoimmune diseases 

 Comprehensive Metabolic Panel (CMP) 

• Glucose: 70–99 mg/dL (fasting) 

• High: Diabetes, stress, infection, steroids 

• Low: Hypoglycemia, insulin overdose, adrenal insufficiency 

• Sodium: 135–145 mmol/L 

• High: Dehydration, kidney disease, excess salt intake 

• Low: Heart failure, SIADH (syndrome of inappropriate antidiuretic hormone), diuretics 

• Potassium: 3.5–5.1 mmol/L 

• High: Kidney disease, acidosis, certain medications (ACE inhibitors, spironolactone) 

• Low: Diuretics, vomiting, diarrhea, low magnesium 

• Calcium: 8.5–10.2 mg/dL 

• High: Hyperparathyroidism, cancer, excessive vitamin D 

• Low: Hypoparathyroidism, kidney disease, low vitamin D 

• Creatinine: 0.6–1.3 mg/dL 

• High: Kidney disease, dehydration, high protein intake 

• Low: Muscle loss, liver disease, pregnancy 

• Blood Urea Nitrogen (BUN): 6–20 mg/dL 

• High: Kidney disease, dehydration, high protein diet 

• Low: Liver disease, malnutrition, overhydration 

• ALT (Liver Enzyme): 7–55 U/L 

• High: Liver damage (hepatitis, fatty liver, alcohol use, medications) 

• Low: Usually not concerning 

• AST (Liver Enzyme): 8–48 U/L 

• High: Liver disease, muscle damage, heart attack 

• Low: Usually not concerning 

 Lipid Panel 

• Total Cholesterol: <200 mg/dL 

• High: Poor diet, genetics, lack of exercise 

• Low: Malnutrition, hyperthyroidism 

• LDL (“Bad” Cholesterol): <100 mg/dL 

• High: Poor diet, genetics, diabetes 

• Low: Hyperthyroidism, malabsorption 

• HDL (“Good” Cholesterol): >40 mg/dL (men), >50 mg/dL (women) 

• High: Regular exercise, good diet 

• Low: Smoking, poor diet, metabolic syndrome 

• Triglycerides: <150 mg/dL 

• High: Diabetes, obesity, excessive alcohol intake 

• Low: Malnutrition, hyperthyroidism 

 Thyroid Function Tests (TSH, T3, T4) 

• TSH (Thyroid-Stimulating Hormone): 0.4–4.0 mIU/L 

• High: Hypothyroidism, iodine deficiency 

• Low: Hyperthyroidism, pituitary dysfunction 

• T3 (Triiodothyronine): 80–180 ng/dL 

• High: Hyperthyroidism, Graves’ disease 

• Low: Hypothyroidism, starvation, chronic illness 

• T4 (Thyroxine): 5.0–12.0 µg/dL 

• High: Hyperthyroidism, thyroid hormone overuse 

• Low: Hypothyroidism, iodine deficiency 

 Vitamin D & B12 

• Vitamin D (25-hydroxyvitamin D): 30–100 ng/mL 

• High: Excess supplementation 

• Low: Lack of sunlight, poor diet, malabsorption 

• Vitamin B12: 200–900 pg/mL 

• High: Liver disease, leukemia 

• Low: Pernicious anemia, vegan diet, malabsorption 

 Inflammation & Autoimmune Markers 

• ANA (Antinuclear Antibody): Negative or within reference range 

• Positive: Autoimmune diseases (Lupus, rheumatoid arthritis, scleroderma) 

• ESR (Erythrocyte Sedimentation Rate): <20 mm/hr (men), <30 mm/hr (women) 

• High: Inflammation, infection, autoimmune diseases 

• Low: Sickle cell disease, polycythemia 

• CRP (C-Reactive Protein): <1.0 mg/L (low risk for heart disease) 

• High: Inflammation, infection, cardiovascular disease 

• Low: Normal, no clinical concern 

 Diabetes Monitoring (A1C) 

• Normal: <5.7% 

• Prediabetes: 5.7%–6.4% 

• Diabetes: ≥6.5% 

• High: Poorly controlled diabetes 

• Low: Rare—could be anemia or chronic blood loss 

 Prostate-Specific Antigen (PSA) – For Men 

• Normal: <4.0 ng/mL (varies with age) 

• High: Prostate cancer, prostatitis, benign prostatic hyperplasia 

• Low: Not usually concerning 

Final Thoughts 

Lab results don’t tell the whole story—your symptoms, history, and overall health matter too! If anything looks off, don’t panic. Your provider is here to help you make sense of it all. 

 Have questions? Book an appointment today! 

Kristen Balconi, RN Care Manager