LAL Endotoxin Test — Standard Operating Procedure

1. Pre-Operation

• [ ] Verify LAL reagent lot and sensitivity
• [ ] Confirm CSE vial opened and dated
• [ ] Prepare LRW (LAL Reagent Water)
• [ ] Check incubation block at 37 ± 1 °C

2. Sample Preparation

1. Dissolve peptide in LRW (1 mg/mL)
2. Adjust pH to 6.0 – 8.0 if needed
3. Prepare serial dilutions (1:10, 1:100, 1:1000)
4. Prepare positive product control (PPC) with 2λ CSE spike

3. Test Procedure

1. Add 0.1 mL sample or control to each tube
2. Add 0.1 mL LAL reagent
3. Mix gently
4. Incubate at 37 ± 1 °C for 60 ± 2 min
5. Read results (gel clot: invert 180° — stable gel = positive)

4. Interpretation

Result	Interpretation
Negatives: no gel	Valid test
Positives: all gel	Valid test
PPC: gel	No inhibition
PPC: no gel	Inhibition present — dilute further