# AI instructs a nurse to dilute insulin for IV infusion using normal saline instead of the manufacturer-recommended diluent, causing insulin precipitation

- **ID:** `medical/insulin-dilution-error`
- **Domain:** medical
- **Category:** config_error
- **Error Code:** `INSULIN-PRECIP-003`
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Regular insulin (e.g., Humulin R) is compatible with 0.9% NaCl for IV infusion only at specific concentrations; using NS at high concentrations or with certain insulin analogs can cause precipitation and dosing errors.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Humulin R U-100 (Eli Lilly) prescribing info 2023 | active | — | — |
| Novolin R (Novo Nordisk) prescribing info 2023 | active | — | — |
| ISMP Guidelines for IV Insulin Infusions 2022 | active | — | — |

## Workarounds

1. **For Humulin R U-100 IV infusion, dilute 100 units (1 mL) in 100 mL of 0.9% NaCl (final concentration 1 unit/mL). Use a dedicated IV line with a 0.22-micron in-line filter. Do not use D5W or lactated Ringer's without checking compatibility. Example: 'Add 1 mL Humulin R U-100 to 100 mL 0.9% NaCl in a PVC bag.'** (88% success)
   ```
   For Humulin R U-100 IV infusion, dilute 100 units (1 mL) in 100 mL of 0.9% NaCl (final concentration 1 unit/mL). Use a dedicated IV line with a 0.22-micron in-line filter. Do not use D5W or lactated Ringer's without checking compatibility. Example: 'Add 1 mL Humulin R U-100 to 100 mL 0.9% NaCl in a PVC bag.'
   ```
2. **For Novolin R, use only 0.9% NaCl for dilution at 1 unit/mL concentration. If D5W is required for other medications, use a Y-site connector with a separate insulin line. Always inspect the solution for turbidity before administration.** (82% success)
   ```
   For Novolin R, use only 0.9% NaCl for dilution at 1 unit/mL concentration. If D5W is required for other medications, use a Y-site connector with a separate insulin line. Always inspect the solution for turbidity before administration.
   ```

## Dead Ends

- **Use 0.45% NaCl (half-normal saline) as a safer alternative for all insulin dilutions** — Half-normal saline is not recommended for insulin dilution; it can cause hemolysis in IV lines and is not tested for insulin stability. (85% fail)
- **Add albumin to the insulin infusion to prevent adsorption to the IV tubing** — Albumin is not recommended for routine insulin infusions; it may cause foaming and inaccurate dosing, and is not approved for this use. (90% fail)
- **Mix insulin directly into the IV bag without dilution** — Direct addition without proper dilution can cause insulin aggregation and unpredictable dosing; manufacturer guidelines require specific dilution protocols. (95% fail)