The most common and most likely answer to this crossword clue is the 5 plus 5 letter word BLOOD COUNT
I've seen this crossword clue in Independent
B
L
O
O
D
C
O
U
N
T
More clues leading to the result BLOOD COUNT
- Dracula’s health indicator?
- Cell number for Dracula?
- Current passed through three ducks in pointless medical check
- Matter suppressed by family in health check
- Health check for Dracula?
- Examination of various cells in a hospital?
- British doctor could not initially oversee result of a lab test
- Health check is family matter
Buddy explains!

The straight part
We know that "Health check" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case health check = blood count.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.