Blood - Bloods - pluralisation

Why is it that the plural of 'blood' is 'blood' in normal usage but 'bloods' (e.g. 'I'll be taking some bloods') is acceptable in a medical context? Are there any words with similar pluralisation anomalies?

This odd pluralisation may be confined to British English, here are some examples

• http://m.studentmidwife.net/student-midwife-forums-2/clinical-placements-and-electives-8/3845-taking-bloods.html

• "Reasons for taking bloods"

• "When to have bloods tested for progesterone?"

• http://www.mail-to.co.uk/Forum/topic.asp?TOPIC_ID=13134

• http://www.imt.ie/opinion/2011/09/restraint-should-be-last-alternative-in-taking-bloods.html

UPDATE: I'm struggling to find online examples of this usage outside of midwifery as per the links above. Now I'm wondering if 'bloods' is actually a pluralisation that refers to both the mother and baby's blood. Has anyone an example of a medical usage outside of pregnancy?

Solution 1:

"Bloods" is not a plural of "blood", but rather, the shortening of "blood test", often among medical professionals. Thus, that explains why "bloods" is acceptable in a medical context.

Solution 2:

There is no plural blood – it is an uncountable noun.

Blood in medical context probably is a slang term for blood sample or blood test, as @Thursagen points out, which makes it countable and subject to normal pluralization rules.

Solution 3:

I don't know where you have been but the term bloods is used on a daily basis in hospitals and doctors surgeries. It is totally wrong to use bloods when referring to one person as they only have one blood. But it is correct when referring to a number of people.

Solution 4:

The word "blood" is considered "uncountable", so grammatically it always remains singular.

The only time I'm aware of the word "bloods" being usable is in reference to the LA street gang. In that case it makes sense because a "Blood" is a member of the gang, and people are countable.

So if someone says, "I'll be taking some bloods", the only way I know to interpret that is that they are bringing along some gang members with them.