| Кровь инфекционного больного может быть опасна. | The blood of a contagious patient can be dangerous. |
| Кровь его была густая и тёмная. | His blood was thick and dark. |
NB When the word кровь functions as a subject and does not have a descriptive modifier, the construction кровь у + Genitive is often preferred to (a) and (b), above: | |
| Кровь у него была густая и тёмная. | His blood was thick and dark. |
| Кровь на губе (or на лбу, etc.) быстро высохла. | The blood on his lip (or on his forehead, etc.) dried quickly. |