Calcium, Albumin relationship

[RuralArizona]

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So...in the circumstance of a patient with a low albumin and a low total calcium, it would be my understanding that the calcium may in fact be normal when utilizing the Corrected Calcium algorithm.

Why then, is hypoalbuminemia a leading cause of hypocalcemia?

Explain it to me like I'm stupid, because I am.

 

[dfib slim]

Why then, is hypoalbuminemia a leading cause of hypocalcemia?

Where did you see this?

 

[RuralArizona]

Where did you see this?

It was briefly mentioned in a textbook I have, so I googled it and admittedly there were few results. But here is one.....http://emedicine.medscape.com/article/241893-overview#a6

 

[theonlytycrane]

albumin is a blood protein that helps to transport stuff around, one of those stuffs being ions. Calcium is one of those ions.

Low albumin -> low calcium transport in the blood.

 

[RuralArizona]

albumin is a blood protein that helps to transport stuff around, one of those stuffs being ions. Calcium is one of those ions.

Low albumin -> low calcium transport in the blood.

Yeah, but as in my initial example, would that not simply equate to a greater proportion of ionized calcium?

 

[theonlytycrane]

Yeah, but as in my initial example, would that not simply equate to a greater proportion of ionized calcium?

can you clarify your question? hypocalcemia is low blood calcium levels.

 

[dfib slim]

Yeah, but as in my initial example, would that not simply equate to a greater proportion of ionized calcium?

Most labs measure serum total calcium but the active form is ionized and not bound to albumin. So say you have a patient in the hospital you checked labs on. You find their serum calcium is low at 7mg/dL (normal is around 8.5-10.5) so you are thinking the have hypocalcemia. You check an albumin and it comes back a 2g/dL (normal is 4).

So you use the formula Corrected Ca = measured Ca + 0.8(4 - serum albumin) which comes out to 8.6. So even though their calcium measured 7 and appeared hypocalcemic they aren't. So it's not like the hypoalbuminemia directly causes hypocalcemia, it just makes it appear that way and is the purpose for using the formula. A typical exam question would give you the above patient and ask do you give them calcium or increase the protein in the diet.

 

[RuralArizona]

Most labs measure serum total calcium but the active form is ionized and not bound to albumin. So say you have a patient in the hospital you checked labs on. You find their serum calcium is low at 7mg/dL (normal is around 8.5-10.5) so you are thinking the have hypocalcemia. You check an albumin and it comes back a 2g/dL (normal is 4).

So you use the formula Corrected Ca = measured Ca + 0.8(4 - serum albumin) which comes out to 8.6. So even though their calcium measured 7 and appeared hypocalcemic they aren't. So it's not like the hypoalbuminemia directly causes hypocalcemia, it just makes it appear that way and is the purpose for using the formula. A typical exam question would give you the above patient and ask do you give them calcium or increase the protein in the diet.

That completely answers my question. Thank you SO much!