Lab Values Quick Reference (NCLEX)

Vocabulary flashcards covering normal laboratory ranges, clinical significance of abnormal values, and NCLEX critical alerts for quick exam review.

Sodium (Na⁺)

135–145 mEq/L. ↑: Dehydration, Cushing’s, diabetes insipidus. ↓: SIADH, fluid overload, renal failure. Critical

Potassium (K⁺)

3.5–5.0 mEq/L. ↑: Renal failure, tissue damage, acidosis (cardiac arrest risk >6.5). ↓: Diuretics, vomiting, diarrhea (arrhythmias risk <2.5).

Calcium (Ca²⁺)

8.5–10.5 mg/dL. ↑: Hyperparathyroidism, malignancy. ↓: Hypoparathyroidism, vitamin D deficiency.

Magnesium (Mg²⁺)

1.5–2.5 mEq/L. ↑: Renal failure, excessive intake. ↓: Alcoholism, malnutrition, diuretics.

Chloride (Cl⁻)

95–105 mEq/L. ↑: Dehydration, metabolic acidosis. ↓: Vomiting, metabolic alkalosis.

Phosphate (PO₄³⁻)

2.5–4.5 mg/dL. ↑: Renal failure. ↓: Alcoholism, malnutrition.

Blood Urea Nitrogen (BUN)

10–20 mg/dL. ↑ indicates kidney dysfunction or dehydration.

Creatinine

0.6–1.2 mg/dL. ↑ suggests impaired renal function.

Glomerular Filtration Rate (GFR)

90 mL/min/1.73 m². ↓ signifies kidney disease.

Fasting Blood Glucose

70–110 mg/dL. ↑: Diabetes, Cushing’s, stress (critical >400). ↓: Insulin overdose, Addison’s, starvation (critical <50).

White Blood Cells (WBC)

5,000–10,000 / mm³. ↑ infection; ↓ immunosuppression.

Red Blood Cells (RBC)

4.2–6.0 million/µL. ↓ indicates anemia.

Hemoglobin (Hgb)

Female 12–16 g/dL; Male 14–18 g/dL. ↓: anemia, blood loss.

Hematocrit (Hct)

Female 36–48 %; Male 42–52 %. ↓: anemia, bleeding.

Platelets

150,000–400,000 / mm³. ↓ <50,000 ⇒ bleeding risk; critical <50,000 ⇒ spontaneous bleeding.

Prothrombin Time (PT)

11–14 sec; monitors warfarin therapy.

International Normalized Ratio (INR)

0.8–1.2 normal. Therapeutic on warfarin 2–3. ↑>4 ⇒ high bleeding risk.

Activated Partial Thromboplastin Time (aPTT)

25–35 sec. Therapeutic 1.5–2× normal for heparin.

Albumin

3.5–5.0 g/dL. ↓ in liver disease or malnutrition.

Total Bilirubin

0.1–1.2 mg/dL. ↑ in liver dysfunction or biliary obstruction.

B-type Natriuretic Peptide (BNP)

Arterial pH

7.35–7.45. ↓ acidosis; ↑ alkalosis.

PaCO₂

35–45 mm Hg. ↑ respiratory acidosis; ↓ respiratory alkalosis.

HCO₃⁻ (Bicarbonate)

22–26 mEq/L. ↓ metabolic acidosis; ↑ metabolic alkalosis.

PaO₂

80–100 mm Hg. ↓ indicates hypoxemia.

SpO₂ (Pulse Oximetry)

95–100 %. ↓ suggests hypoxia.

NCLEX Critical Alert – Potassium

NCLEX Critical Alert – Sodium

NCLEX Critical Alert – INR

4 = high bleeding risk.

NCLEX Critical Alert – Blood Glucose

NCLEX Critical Alert – Platelets