DrBaboon
11-22-05, 18:56
I have been aware of refractometers being used for estimating protein content of blood serum for a long time, but never bothered with it due to having easy availability of reports from automated clinical laboratories.
Since I had mentioned refractometry here not too long ago as applied to urine specific gravity, I thought I'd mention it as a means of protein estimation.
My refractometer has 3 scales - urine specific gravity, a solute scale and a protein scale. This yields total protein if serum is place onto the refractometer.
It doesn't solve the question of globulins vs. albumin (much less any other insights into globulins). By itself, I can't say that serum total protein is an essential test, but it could be helpful when combined with other clinical information and simple laboratory data. Its role would be mostly in diagnosis and management of medical illness - for example - conditions which have elevated serum proteins (which also raises the question of whether there's anything you can do about something like multiple myeloma).
The other use would seem to be in looking at fluid drained from a body cavity, and would be helpful in determining transudate vs. exudate. I could also imagine looking at cerebrospinal fluid for protein, if it were combined with a CSF glucose, gram stain, and cell count. This might turn out to the more helpful use for protein estimation (body cavity fluid and CSF).
Simple searches on the web bring up articles which extol the virtues of protein via refractometer, as well as articles critical of it. Some of them are from human studies, some from veterinary sources. There are also examples of differing veterinary opinions depending on animal species (for some reason, refractometer protein estimates have not correlated well with chemically measuring serum protein in birds). Apparently, significant amounts of acetone in serum or fluid alters refraction in a way to make protein estimation by refractometer unreliable (which should be a circumstance that we can recognize or anticipate).
On the whole, I'm not sure there's an easier way than refractometry to get this type of information under austere conditions, and it's not expensive, and doesn't consume reagents or use electricity. If it's also used for a portion of urinalysis, it also means getting at least double duty out of one instrument -- more than double duty if you allow for estimating protein in tracheal fluid or body cavity fluid or CSF.
Since I had mentioned refractometry here not too long ago as applied to urine specific gravity, I thought I'd mention it as a means of protein estimation.
My refractometer has 3 scales - urine specific gravity, a solute scale and a protein scale. This yields total protein if serum is place onto the refractometer.
It doesn't solve the question of globulins vs. albumin (much less any other insights into globulins). By itself, I can't say that serum total protein is an essential test, but it could be helpful when combined with other clinical information and simple laboratory data. Its role would be mostly in diagnosis and management of medical illness - for example - conditions which have elevated serum proteins (which also raises the question of whether there's anything you can do about something like multiple myeloma).
The other use would seem to be in looking at fluid drained from a body cavity, and would be helpful in determining transudate vs. exudate. I could also imagine looking at cerebrospinal fluid for protein, if it were combined with a CSF glucose, gram stain, and cell count. This might turn out to the more helpful use for protein estimation (body cavity fluid and CSF).
Simple searches on the web bring up articles which extol the virtues of protein via refractometer, as well as articles critical of it. Some of them are from human studies, some from veterinary sources. There are also examples of differing veterinary opinions depending on animal species (for some reason, refractometer protein estimates have not correlated well with chemically measuring serum protein in birds). Apparently, significant amounts of acetone in serum or fluid alters refraction in a way to make protein estimation by refractometer unreliable (which should be a circumstance that we can recognize or anticipate).
On the whole, I'm not sure there's an easier way than refractometry to get this type of information under austere conditions, and it's not expensive, and doesn't consume reagents or use electricity. If it's also used for a portion of urinalysis, it also means getting at least double duty out of one instrument -- more than double duty if you allow for estimating protein in tracheal fluid or body cavity fluid or CSF.