| Answer | Crossword Clue |
|---|---|
| PUREBLOOD | Virus-free serum |
| seronegative | Giving a negative result in a test of blood serum, e.g., for the presence of a virus |
| seropositive | Giving a positive result in a test of blood serum, e.g., for the presence of a virus |
| haptoglobin | A protein present in blood serum that binds to and removes free hemoglobin from the bloodstream |
| CLEAN | Virus-free |
