Cryptic crossword clue
Is after single old coin in unusual means test 13

The most common and most likely answer to this crossword clue is the 13 letter word AMNIOCENTESIS

A
M
N
I
O
C
E
N
T
E
S
I
S

Buddy explains!

The straight part
We know that "test" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case test = amniocentesis.
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.

What does AMNIOCENTESIS mean?

AMNIOCENTESIS noun
  1. A procedure for obtaining amniotic fluid from a pregnant animal, by inserting a hollow needle through the abdominal wall and into the amniotic sac. Used in diagnosing possible genetic defects and/or obstetric complications.

Latest crossword clues with full explanations