RN Clinical Fundamentals

01Normal adult vital sign ranges

Heart rate 60-100 bpm, respiratory rate 12-20/min, blood pressure around 120/80 mmHg, temperature 97.8-99°F (36.5-37.2°C), and SpO2 95-100%. Values outside these ranges should be reported, not just charted.

02A1C reflects long-term glucose control

Hemoglobin A1C reflects average blood glucose over roughly the past 2-3 months (tied to the ~3-month red blood cell lifespan). Normal is under 5.7%, prediabetes is 5.7-6.4%, and diabetes is 6.5% or higher.

03Fasting blood glucose ranges

Normal fasting glucose is 70-99 mg/dL, prediabetes is 100-125 mg/dL, and diabetes is diagnosed at 126 mg/dL or higher on repeat testing (ADA criteria).

04Potassium and why it matters

Normal serum potassium is 3.5-5.0 mEq/L. Elevated potassium (hyperkalemia) is dangerous because it can trigger life-threatening cardiac arrhythmias, so a significantly high value warrants prompt provider notification.

05Anticoagulant monitoring labs

aPTT (therapeutic range roughly 1.5-2.5x control, about 50-80 seconds) is used to monitor IV heparin; INR (therapeutic range 2-3) is used to monitor warfarin. Mixing these up is a common error.

06When to escalate a finding

Any vital sign meaningfully outside normal range, new confusion, or a dangerous lab value should be reported to the provider or charge nurse promptly rather than simply documented for the next round.