Final answer:
In a concentrated urine sample, red blood cells will typically present as crenated due to dehydration from a hyperosmotic environment, leading to a shrunken, spiky appearance.
Step-by-step explanation:
The type of red blood cell that may be seen in a concentrated urine sample is typically a crenated cell.
When red blood cells are exposed to a hyperosmotic environment, like that of concentrated urine, they lose water through osmosis. This dehydration causes the red blood cells to shrink and assume a wrinkled, spiky appearance known as crenation. Crenated red blood cells are not able to function effectively; the densification of solutes within them interferes with normal cellular processes, which can lead to the cell's death. In contrast, red blood cells swell in hypotonic solutions due to the influx of water, but this does not happen in a concentrated urine sample where the environment is not hypotonic. Colourless cells would only occur if the red blood cells were lysed, which is not indicated in this context.