The colour of blood...

[Jon_in_london]

Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

[geni]

Well you can see that your veins are blue so you should be able t see the difference. I remember My biology tescher mentioning that before they brough in some of the more recent safly regs he used to do a demostration involving bubbleing CO2 and O2 through a test tube of blood and you could see a difference.

[Rolfe]

Originally posted by Jon_in_london
Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye? Spectra is plural. Spectrum is singular. Spectras is ungrammatical. End of lecture.

Yes you can tell the difference.

Doing a post-mortem, the blood comes out of the veins and pools on the table, dark red. As it is exposed to the air it develops a bright red film of oxygenated blood. Very obvious to the naked eye.

If you're taking a blood sample and aiming for venous blood, the other thing which tells you you've hit an artery (apart from your patient kicking you in the teeth) is that the blood in the syringe is bright red.

And that's animal blood. Human venous blood is weird, it's so dark it's not really red at all, it's almost black. So I think the difference will be even more obvious. If you cut a finger, that's capillary blood, which is sort of in between, quite oxygenated really, and of course it is in contact with the air so that also has an effect. If you've ever had a blood sample taken, though, or given blood, it's easy to see that the blood coming out of the vein into the syringe or collection pack (and so not exposed to the air) is very dark.

OK?

Rolfe.

[Hand Bent Spoon]

^Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.

Correcting someone's etiquette, even when they commit a faux pas, is impolite unless you are their parent or etiquette coach. So shame on me.

:D

[LucyR]

Originally posted by Hand Bent Spoon
Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.


'advise'?

[roger]

Oh, this thread is going to get ugly. And fast. :D

[espritch]

Oh, this thread is going to get ugly. And fast.

Yeah. If it continues in this vein, it could coagulate into a regular blood bath. And wouldn't that be humorous? ;)

[davefoc]

I thought the question was very interesting and I was interested in the response. Thank you Rolfe.

I don't think, it was mentioned but I am under the impression that the notion that blood is ever blue is false and that any blue appearance is because we see the blood in our veins through our skin (usually).

[Cecil]

Originally posted by espritch
Yeah. If it continues in this vein, it could coagulate into a regular blood bath. And wouldn't that be humorous? ;) Now you're getting to the heart of the matter. But, I'm still sanguine about the outcome of this thread - I don't think blood will be spilt. :D

[LucyR]

Originally posted by Cecil
Now you're getting to the heart of the matter. But, I'm still sanguine about the outcome of this thread - I don't think blood will be spilt. :D

Yes, fortunately blood's thicker than water.

[Zep]

Originally posted by davefoc
I thought the question was very interesting and I was interested in the response. Thank you Rolfe.

I don't think, it was mentioned but I am under the impression that the notion that blood is ever blue is false and that any blue appearance is because we see the blood in our veins through our skin (usually). If I recall, "blue blood" looked blue simply because the owner's skin, through which their veins showed, was usually a very pale (i.e. pasty) white. That is, they were upper classes, hence "bluebloods". As opposed to the lower classes whose skin was was stained much darker brown due to long hard days gathering muck on the muck-farms to be shipped to the muck-factories.

Or so I was told.

[espritch]

Just as a point of interest, the blood of horse shoe crabs really is blue. IIRC it is copper based rather than iron based.

Sorry to interupt the bloody pun fun, but I had a feeling that topic had about been bled dry anyway.

[JamesM]

Originally posted by Jon_in_london
Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?
Absorption spectra for all sorts of states of haemoglobin can be found here:

http://www.medphys.ucl.ac.uk/research/borg/research/NIR_topics/spectra/spectra.htm

Why not plug 'em into a spreadsheet and have a look? I tried it with adult hbO2 and hbCO, and they were indeed different. No idea if that's different enough to detect by eye, but if Rolfe says yes, that's good enough for me.

[Rolfe]

Would it help if I said sorry? :(

I once saw the item "Gateaux's" on offer in a cafeteria in St Peter Port, and I think it scarred my psyche for life.

Your repentant,

Rolfe.

[Ladewig]

Shame on me

Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.



Because "someone" is singular and "their" is plural, you have violated the pronoun/antecedent rule.

[davefoc]

Because "someone" is singular and "their" is plural, you have violated the pronoun/antecedent rule.

Does this rule still apply today? Previously, the acceptable wording might have replaced "their" with "his", but I think today's style is to avoid the use of "his" where it describes something that belongs either to a male or a female.

[Cecil]

Originally posted by davefoc


Does this rule still apply today? Previously, the acceptable wording might have replaced "their" with "his", but I think today's style is to avoid the use of "his" where it describes something that belongs either to a male or a female. I think the language is changing. Their seems to be becoming more and more accepted as a singular pronoun, to avoid the awkward yet politically correct term "his or her".

[Camillus]

Originally posted by Jon_in_london
Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

You're right: you can't tell the difference with the naked eye. You can infer that the bright red colour is COHb from the circumstances but there is no discernible visual difference, in my experience, between well oxygenated blood and blood with a high CO content.

Cheers

[Rolfe]

Originally posted by Camillus
there is no discernible visual difference, in my experience, between well oxygenated blood and blood with a high CO content.Er, CO content? We were talking about CO<SUB>2</SUB> content, unless I've totally got hold of the wring end of the stick.

And in my experience the colour of that is quite different. Carbon monoxide poisoning is another matter which I didn't think anyone had raised.

The blue-blood thing has been well explained. Venous blood does look blue-ish when seen through thin, white, non-sunburned skin.

(I think the "their" thing is acceptable, but the use of "advise" when "advice" was meant, is om mare shaky ground.)

Rolfe.

[Camillus]

Originally posted by Rolfe
Er, CO content? We were talking about CO<SUB>2</SUB> content, unless I've totally got hold of the wring end of the stick.

And in my experience the colour of that is quite different. Carbon monoxide poisoning is another matter which I didn't think anyone had raised.

I think you've got the wrong end of the stick :). Carboxyhaemoglobin occurs in the presence of CO . CO<SUB>2</SUB> produces carbaminoglobin, since it binds to the globin rather than the haem part of the molecule.


Cheers

[Rolfe]

Originally posted by Camillus
I think you've got the wrong end of the stick :). You may be right, I can never keep those terms straight.

I thought the original questioner was just asking about the difference between oygenated and deoxygenated blood, and the follow-up about blue-bloodedness would seem to back up that interpretation. Ah, but that wasn't the same person, was it....?

My specialist haematology texts don't cover this point.

Digs around in elderly physiology text.... Rather good chapter on blood pigments.... Complete amino acid structures of Hb alpha and beta chains.... Sickle cell haemoglobin (HbS)....

Oxygenated haemoglobin is referred to as "oxyhaemoglobin", with you so far, and the distinction between this and methaemoglobin (oxidised haemoglobin) highlighted.

Yes, you're right, the CO product is referred to as "carboxyhaemoglobin", not, as I had erroneously remembered, "carbonmonoxyhaemoglobin". (Interesting aside, "Up to 5% of the haemoglobin in the blood of heavy tobacco smokers may be in the form of carboxyhaemoglobin.") The word "carbaminoglobin" isn't actually mentioned, but may not be relevant to that section of the text.

So, I was in actual fact, entirely wrong. And thanks for the prompt to revise something learned so long ago that I hadn't realised my memory was faulty.

I thought he was simply asking if you could tell venous from arterial blood by eye. If the question really is, can you actually tell carbon-monoxide-poisoned blood from normal arterial oxygenated blood by eye, you're right, I don't know. I suspect that it is the presence of bright red blood on the venous side of the circulation which is the diagnostic giveaway, rather than the exact hue of the brightness of the red.

I obviously need more sleep or something, I'm not fit for civilised discourse. :(

Rolfe.

[Ziggurat]

Originally posted by geni
Well you can see that your veins are blue so you should be able t see the difference. I remember My biology tescher mentioning that before they brough in some of the more recent safly regs he used to do a demostration involving bubbleing CO2 and O2 through a test tube of blood and you could see a difference.

Blue veins in the skin is actually largely due to different penetration depths for red and blue light inside your body. Arteries near the skin would also look more blue than they actually are, but there aren't really any near the skin. Not that this says anything about whether or not you can distinguish oxygenated blood based on color, merely that your skin affects the color.

[davefoc]

I gave blood today and asked the phlebotomist the question about the color of blood. She had the same answer as was previously provided about the light and dark blood.

But this inspired another question: Do they ever hit an artery by accident. The answer was yes it happens occasionally, apparently its a bit messy as the arterial blood is at a much higher pressure and can really squirt. But I guess it's not that big a deal because they can handle the problem right there.

Anyway, I was talking to my buddy about this today and he had totally bought into the veinal blood is blue because of the lack of oxygen thing. When I told him that was a myth, he asked about why when the body is deprived of oxygen the lips turn blue if wasn't because the blood in them had less oxygen. Anybody know what the answer to this question is?

[Rolfe]

Um, at the risk of making a complete prat of myself (again), deoxygenated blood seen through skin does look sort of blue, so I don't see what's wrong with saying the lips turn blue because the blood in them has less oxygen. (Now I fully expect someone to tell me exactly what's wrong with it....)

But it looks as if the original question was actually about telling the difference between normally oxygenated blood and blood poisoned by carbon monoxide, which is probably that you can't, it's just that blood that colour in the veins (as opposed to the arteries) is seriously abnormal.

Rolfe.

[Eos of the Eons]

My skin is very see through. I can tell the veins from everything else because they are very blue. It does not matter how close to the skin they are compared to my arteries. I can seen an artery under a veing in my arm here, and it is very clearly more red. All of my veins seem closer to the surface of my skin than my arterie. Any arteries close to my skin are much smaller than the veins close to the surface.

[Boo]

Ok, I'll take a stab at it.

Having been exposed (literally) to large amounts of de-oxygenated blood, oxygenated blood outside of the body the difference is indeed noticable.

As for CO saturated blood because of the binding with the hemoglobin it is indeed a brighter red then 'normal' venous blood. This is what gives the
characteristic 'cherry red' appearance to the skin in the late stages of CO poisoning.


IIRC cyanosis (turning blue) is from deoxygenation since the body is trying to protect itself by moving all the oxygenated blood to the core organs (heart, brain, lungs and kidneys). Depending on the coloration from pale, mottled, blue, purple and grey it is possible to learn to estimate the severity of of hypoxia. Although factors such as ambient temperature and baseline can confuse things.


Boo

[Rolfe]

Originally posted by Boo
As for CO saturated blood because of the binding with the hemoglobin it is indeed a brighter red then 'normal' venous blood.Yes, but is it a different shade from normal arterial blood?

Rolfe.

[Boo]

Rolfe,

Best guess off the top of my head is that it would depend on the saturation level. If the CO venous is saturated to anywhere near the 90% mark then yes, otherwise probably not. Would you be able to differentiate between the two? Again probably not. It becomes a matter of subjective assesment due to vision.


Boo