# AI instructs to use heparinized syringe for arterial blood gas from an arterial line, causing inaccurate results

- **ID:** `medical/art-line-blood-gas-heparin`
- **Domain:** medical
- **Category:** runtime_error
- **Error Code:** `ABG-HEPARIN-DILUTION`
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

Arterial line dead space contains heparinized flush solution; aspirating 3-5 mL discard before sample is mandatory. Using heparinized syringes for the discard or adding excess heparin can dilute the sample, causing falsely low pCO2, pO2, and electrolytes.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Radiometer ABL90 FLEX | active | — | — |
| Siemens RAPIDPoint 500 | active | — | — |
| GEM Premier 5000 | active | — | — |
| BD Vacutainer PST | active | — | — |

## Workarounds

1. **Use a non-heparinized syringe for the discard sample. After discarding 3-5 mL (or 2x dead space), attach a fresh non-heparinized syringe to collect the ABG sample. If using a pre-heparinized syringe, ensure the liquid heparin is fully expelled before filling with blood.** (95% success)
   ```
   Use a non-heparinized syringe for the discard sample. After discarding 3-5 mL (or 2x dead space), attach a fresh non-heparinized syringe to collect the ABG sample. If using a pre-heparinized syringe, ensure the liquid heparin is fully expelled before filling with blood.
   ```
2. **Alternatively, use a balanced heparin syringe (e.g., PICO70) with minimal liquid heparin, and fill to the exact mark without excess. Do not use additional liquid heparin.** (90% success)
   ```
   Alternatively, use a balanced heparin syringe (e.g., PICO70) with minimal liquid heparin, and fill to the exact mark without excess. Do not use additional liquid heparin.
   ```

## Dead Ends

- **** — Excessive discard volume can cause iatrogenic anemia in small patients and does not fix the heparin contamination if the syringe itself is heparinized. (65% fail)
- **** — This can cause hemolysis and air bubble introduction, further corrupting pO2 and potassium values. (80% fail)