Serum Protein Values in Wound Care: Let Us Save Some Money

There are thousands of decisions in medicine made everyday that can have impact on the total cost of medical care. This is just one example of how the decision to order a serum protein level for assessment of the care of patients with wounds can actually save millions of dollars every year. Medical leadership also belongs at the bedside where health care decisions made by clinicians every day impact the cost of care. Wrong tests, too many tests, duplication of tests, testing that has no impact or never used greatly impacts the final cost that all of us pay.

Clinicians take information learned from experience and study. They apply that knowledge to help a patient during their illness. Honoring a colleague can be phrased often by the adage of: “She has ‘extensive clinical experience’.”

As wound experts, we know that patients with significant skin injuries require good nutrition. We also know that a potential risk factor for wound development is poor nutrition. For the sake of brevity, I understand that good nutrition means adequate calories (in the form of carbohydrates and fats), protein, vitamins, minerals and fluid for hydration.

Protein status of the body is affected by multiple factors. So upon the initial visit of a patient with a wound you would consider: intake of protein, absorption of the protein in the diet; ability of the liver to produce the protein; understanding the extent of the wound (duration, size, type (burns, for example)); and knowledge about other diseases in which there may be losses (underlying nephrotic syndrome, cancer, other inflammatory diseases). Physical features of inadequate protein intake could manifest itself with muscle wasting, but this could be due to other comorbidities.

The science of determining protein stores in the human body is not so clear cut. You could use any protein that is produced by the body (usually liver), understand the time it takes for that protein to normally degrade in the body, and measure it in the bloodstream so long as there are well-established normal values. In addition, you would want to use values that are readily available through the laboratory and that do not cost too much, especially if you are going to order this test regularly.

The three protein tests that have fulfilled these criteria for a nutritional assessment of the human body are serum albumin, serum transferrin and serum prealbumin (transthyretin). While it depends on the laboratory that you are using (and patient insurance, among other complicated healthcare insurance factors), a serum prealbumin costs about 8–10 times[1] more than a serum albumin.[2] The facts are that a serum albumin has a half-life of about 19 days. A very low serum albumin below 2.2 gm/dL in surgical patients is associated with very poor outcomes. [3] The transferrin has a half-life of about 8 days; it requires some knowledge about the iron stores of a patient, so this test is not used often in assessing protein stores. The prealbumin has a half-life of 2 to 3 days, so it could be useful in understanding recent nutritional intake in a patient. However, the production of prealbumin is very sensitive to inflammation (as with our patients with extensive wounds).

When you look at correlation of either albumin or prealbumin and outcomes for various endpoints (surgical patients, elderly patients, nursing home patients, wound care, etc.) the data do not support one value over another consistently.[4] Very low values can provide additional supplementary information about the nutritional status of a patient and trigger an expedited intervention with a dietician.

A serum prealbumin can reflect a more recent protein intake compared to serum albumin, but it is not a better, nor smarter test than a serum albumin to determine protein stores in the human body. The intervention for a patient with a wound would be to increase nutrition (and protein). Wound care clinicians should consider not ordering the prealbumin as it is fraught with the same interpretation issues for protein stores as the serum albumin test and costlier.

[1] For example, a recent visit to the local outpost of a well-known laboratory revealed that an albumin costs $25.00 and a prealbumin costs $129.72; note that a Complete Metabolic Panel only costs $17.00 (and includes the albumin).

[2] Am Surg. 2011 Oct;77(10):1286–9.

[3] http://www.uptodate.com/contents/overview-of-perioperative-nutritional-support?source=machineLearning&search=prealbumin&selectedTitle=8~66&sectionRank=3&anchor=H3#H6

[4] http://www.woundsource.com/blog/albumin-and-pre-albumin-are-they-markers-nutritional-status-wound-management

© February 27, 2016 Scott Matthew Bolhack, MD, MBA, CMD, CWS, FACP, FAAP