Thread by @TWDFNR

1/ Why is "Prealbumin Testing to Diagnose Malnutrition in the Hospitalized Patient" a #TWDFNR?

This #tweetorial is meant to complement the recent publication of the same name in @JHospMedicine

journalofhospitalmedicine.com/jhospmed/artic…

2/
Let’s start with two questions...

First: Do you use prealbumin as a “marker” of malnutrition?

3/
Second: How did prealbumin get its name?

[GE = gel electrophoresis]

4/
Preablumin gets its name from the fact that it runs anode (i.e., before or "pre") albumin on a gel electrophoresis (see Picture).

But, "prealbumin" is an outdated (and misleading) name. It's more appropriate name is transthyretin. For this thread, we'll stick with prealbumin.

5/
Two reasons why you might think prealbumin offers value:

✔️it's shorter half-life (3d vs 3w for albumin) means it may reflect rapid changes in nutrition
✔️early studies of children with protein-calorie malnutrition suggested a correlation

ncbi.nlm.nih.gov/pubmed/4113892

6/
But, as Lacy, Roesch, and Langsjoen discuss, recent literature suggests that prealbumin is:

✔️not sensitive/specific for malnutrition
✔️not always responsive to nutritional interventions
✔️not always correlated with health outcomes

For this thread, I'll discuss the first.

7/
re: Sensitivity

As noted in a systematic review by Lee et al, in patients WITHOUT inflammatory conditions, prealbumin may be normal until one has severe malnutrition (e.g., the BMI falls below 12).

ncbi.nlm.nih.gov/pubmed/25912205

8/
re: Specificity

As shown in Table 1 of the #TWDFNR paper, there are many things (other than nutritional status) that affect prealbumin.

One key example: just like albumin, prealbumin is a negative acute phase reactant (i.e., it decreases in many inflammatory states).

9/
Before closing, let's ask a version of one of the original question.

Do you use prealbumin as a “marker” of malnutrition?

10/
To summarize, though many of us have used prealbumin (transthyretin!) as a marker of nutritional status, it fails on many counts. As a result, it is a #TWDFNR.

For more information, have a look at the recent paper published in @JHospMedicine

journalofhospitalmedicine.com/jhospmed/artic…