KOH String Test is a rapid bedside/lab test used to differentiate Gram-negative from Gram-positive bacteria without performing Gram stain. 🧪 How it works: Mix a colony with 3% KOH on a slide Gently lift with a loop or stick 🧬 Result interpretation: 🧵 String formation (viscous, sticky thread) → Gram-negative ✅ 👉 Cell wall breaks → DNA released ❌ No string → Gram-positive ⚡ Why it’s useful: Faster than Gram stain Helpful when Gram stain is unclear Great for teaching & quick screening 📌 Rememb