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Nursing Clinical Cheat Sheets: Lab Values, ABG Interpretation and ECG Anchors
A nursing cheat sheet earns its place only if you can read it in the three seconds you have. Below is the material itself, free: normal adult lab values, the four-step ABG method with ROME, the anion gap, and the ECG anchor numbers — standard textbook references, written by a 13-year ER night-shift nurse.
Written by a 13-year ER night-shift nurse. Free to read here — no sign-up.
The sheets in the printable set all share one design system — same header, same order, same place for the number you are looking for — so your eyes know where to land when a result comes back weird. What follows is the reference content from three of those six sheets, given away here.
Normal adult lab values
| Test | Normal adult range | Notes |
|---|---|---|
| WBC | 4.5–11.0 K/µL | rises with infection, stress, steroids |
| RBC | M 4.7–6.1 / F 4.2–5.4 M/µL | anemia vs polycythemia |
| Hemoglobin | M 13.5–17.5 / F 12.0–15.5 g/dL | transfusion threshold varies by patient |
| Hematocrit | M 41–50% / F 36–44% | roughly 3× Hgb |
| Platelets | 150–400 K/µL | < 50K = bleeding risk discussion |
| Sodium | 135–145 mEq/L | moves water; change slowly |
| Potassium | 3.5–5.0 mEq/L | cardiac first; never IV push |
| Chloride | 98–106 mEq/L | tracks Na and fluids |
| CO₂ (bicarbonate) | 22–29 mEq/L | metabolic buffer |
| BUN | 7–20 mg/dL | hydration + renal |
| Creatinine | 0.6–1.3 mg/dL | best single renal screen |
| Glucose (fasting) | 70–100 mg/dL | capillary vs serum correlate |
| Calcium | 8.5–10.5 mg/dL | correct for albumin |
| Magnesium | 1.7–2.2 mg/dL | pairs with potassium |
| Phosphorus | 2.5–4.5 mg/dL | refeeding risk if low |
| Albumin | 3.5–5.0 g/dL | nutrition + oncotic pressure |
| AST / ALT | 10–40 / 7–56 U/L | liver injury pattern |
| Alk phos | 44–147 U/L | biliary / bone |
| Total bilirubin | 0.3–1.2 mg/dL | liver + hemolysis |
| INR / PT / aPTT | 0.8–1.2 / 9.5–13.5 s / 25–35 s | coagulation cascade |
| Troponin | assay-dependent | interpret per your lab; trend matters |
| Lactate | < 2.0 mmol/L | tissue perfusion |
| HbA1c | < 5.7% | 3-month glucose picture |
Standard adult references. Verify your facility's published reference intervals — ranges vary by lab and assay.
You are not going to memorize twenty-three rows, and you do not need to. Memorize the handful that change management — K⁺, Na⁺, glucose, creatinine, troponin, lactate — and let the page carry the rest.
ABG interpretation: read every gas the same four steps
| Value | Normal |
|---|---|
| pH | 7.35–7.45 |
| PaCO₂ | 35–45 mmHg (respiratory) |
| PaO₂ | 80–100 mmHg |
| HCO₃ | 22–26 mEq/L (metabolic) |
| Base excess | ±2 mEq/L |
| SaO₂ | 95–100% |
The four steps
- Is the pH acidemic (< 7.35) or alkalemic (> 7.45)?
- Which side matches? ROME: Respiratory Opposite (pH ↓ / PaCO₂ ↑), Metabolic Equal (pH ↓ / HCO₃ ↓).
- Is the other side compensating? The kidneys move HCO₃; the lungs move PaCO₂.
- Check the anion gap: Na⁺ − (Cl⁻ + HCO₃⁻) — normal 8–12.
| Disorder | pH | PaCO₂ | HCO₃ |
|---|---|---|---|
| Respiratory acidosis | ↓ | ↑ | normal (early) |
| Respiratory alkalosis | ↑ | ↓ | normal (early) |
| Metabolic acidosis | ↓ | normal (early) | ↓ |
| Metabolic alkalosis | ↑ | normal (early) | ↑ |
Suspicion plus trend beats memorization: one gas is a snapshot, two gases are a story.
ECG anchors worth carrying in your head
Rate = 300 ÷ big boxes. PR 0.12–0.20 s, QRS 0.08–0.12 s, and QT no more than half the RR interval. Those four numbers turn a strip from a picture into a set of measurements — and they are the same anchors printed at the top of the ECG sheet in the set, above a fourteen-rhythm quick table from normal sinus to V-fib.
Electrolytes: the cardiac ones first
| Ion (normal) | Nursing focus |
|---|---|
| Na⁺ 135–145 | confusion, weakness, seizures either direction · slow correction, neuro checks |
| K⁺ 3.5–5.0 | U waves low, peaked T high · cardiac monitor, never IV push potassium |
| Ca²⁺ 8.5–10.5 | tetany and Chvostek/Trousseau low; stones, bones, groans high · cardiac + neuromuscular checks |
| Mg²⁺ 1.7–2.2 | tremor and arrhythmia low, hyporeflexia and bradypnea high · K⁺ will not hold until Mg²⁺ is fixed |
| PO₄³⁻ 2.5–4.5 | refeeding syndrome watch · weakness and rhabdo risk when low |
Signs are classic findings — treat the patient, not the number.
Cardiac rhythm is the tiebreaker for K⁺, Ca²⁺ and Mg²⁺. When in doubt, put them on the monitor.
Why six sheets and not one long page
A reference you have to scroll is a reference you stop using. Each sheet fits on one US Letter page, stands alone, and prints at 100% with no fitting — so you print the set once for the workstation, or print single sheets for the units you rotate through and stop caring when one gets coffee on it. Anything lab-specific, like troponin, is flagged as assay-dependent, because that part genuinely varies by lab.
The printable version
Nursing Clinical Cheat Sheets — $15
Six printable one-page references in one design system: labs, ABG, electrolytes, IV fluids, common meds by class, and ECG rhythms.
- Normal Lab Values, ABG Interpretation, Electrolytes & Common Imbalances
- IV Fluids Quick Reference by tonicity, Common Meds by Class, ECG Rhythm Basics
- US Letter, print at 100% / actual size, personal-use license included
- Every page stands alone, so you only reprint the ones you wear out
Want the med-surg sheet too? The Med-Surg & ER Brain Sheet Combo ($12) pairs a med-surg brain sheet with the full ER night-shift sheet and a floor-agnostic report page.
Standard adult reference ranges, not a protocol. Values, doses and intervals must be verified against your own facility’s references and policies — and this page is a memory aid, not a substitute for the chart, the order, or your clinical judgment.