# What does it mean when your fingernails turn blue?

**URL:** <https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676>\
**Category:** Factual Questions\
**Created:** [September 21, 2005, 12:52pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676 "2005-09-21T12:52:52Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![jebert](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@jebert](https://boards.straightdope.com/u/jebert)\
**Post date:** [September 21, 2005, 12:52pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/1 "2005-09-21T12:52:52Z")

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Last night I looked at my fingernails, and they had a pronounced bluish cast in the area right above the lunula. This morning the color has returned to the normal pinkish hue.

What does the color of one’s fingernails indicate about the state of one’s body or health?

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**Author:** ![John\_F](https://avatars.discourse-cdn.com/v4/letter/j/43a26b/32.png) [@John\_F](https://boards.straightdope.com/u/John_F)\
**Post date:** [September 21, 2005, 1:00pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/2 "2005-09-21T13:00:34Z")

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Did you press on them while the blue was there to see if your nail bed would change color?

I’ve seen them do that to check for circulation after an injury to the arm or leg.

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**Author:** ![Anaamika](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@Anaamika](https://boards.straightdope.com/u/Anaamika)\
**Post date:** [September 21, 2005, 1:03pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/3 "2005-09-21T13:03:27Z")

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Fingernails provide many clues to the body’s state of well-being.

[Cite.](http://en.wikipedia.org/wiki/Fingernails)  
[Cite.](http://www.bellaonline.com/articles/art31078.asp)  
[Cite.](http://www.drbob4health.com/HealthyLivingTips/FingernailHealth.htm)

Do you take your vitamins? Get plenty of iron?

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**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\
**Post date:** [September 21, 2005, 1:03pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/4 "2005-09-21T13:03:37Z")

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Got to third base with Smurfette?

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**Author:** ![Small\_Clanger](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@Small\_Clanger](https://boards.straightdope.com/u/Small_Clanger)\
**Post date:** [September 21, 2005, 4:08pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/5 "2005-09-21T16:08:56Z")

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Low blood oxygen levels?

> [@](#):
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> The blue discoloration of cyanosis is seen most readily in the beds of the fingernails

from [here](http://www.chclibrary.org/micromed/00044590.html). Is this the mechanism used by the little clippy thing they put on your finger to test blood oxygen in hopstiple?

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**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\
**Post date:** [September 21, 2005, 4:19pm UTC](https://boards.straightdope.com/t/what-does-it-mean-when-your-fingernails-turn-blue/322676/6 "2005-09-21T16:19:39Z")

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Carbon monoxide poisoning? Drove my MIL’s car for a while and, since it was very cold outside, monitored my nails to know when I really should open a window. And yes, as a good boy (and at my wife’s insistence) I did tell MIL to have her exhaust system looked at.