Friday, April 17, 2009

Beta-2 Transferrin: The Tau of Trauma

Jeannie Williams, a laboratory technician at Memorial Hospital in Springfield, IL, posed a question about beta-2 transferrin testing on cerebrospinal fluid (CSF). Because beta-2 transferrin is a normal constituent of CSF, but not of plasma or mucosal secretions, it is useful in determining whether a patient's nose or ear is leaking CSF versus some other fluid. This is important in determining whether an occult skull fracture or defect has opened a potential route of infection into the central nervous system. In addition to the CSF, beta-2 transferrin is present in the occular humors and the inner ear fluid, which could be an alternative source of this protein in trauma cases where the central nervous system is not actually breached.  In the hospital laboratory, beta-2 transferrin can be detected electrophoretically by immunofixation. Thanks for the question, Jeannie!

Sources:
Tietz Clinical Guide to Laboratory Tests, 4th Edition, Alan H.B. Wu (editor), Saunders Elsevier 2006, p. 1063-5.

Molecular Biology of the Cell, 4th Edition, Bruce Alberts, et al. (editors), Garland Science 2002, p. 935.

8 comments:

Dolderer said...

Hello Dr. Moore. I will be starting medical school this fall and I am interested in pathology. I know it is rather early for me to be looking at specialties, but from what I have read it seems like it would fit me well. In college I majored in neurobiology and I loved it. I was just curious if you had any short bits of advice for someone in my position. Thanks!

Brian E. Moore, MD said...

Hi, Dolderer. Of course, I encourage your interest in pathology; and since you were a neurobiology major I would encourage you to look into a neuropathology fellowship afterwards. My advice to you for now is to shadow pathologists at your institution as early as possible. Find time even during the first year to visit the pathology department. That way, you'll know early on whether pathology is for you! Good luck, and keep us informed of your progress!

henry brown said...

Brian
Do you use that muscle biopsy book ( Muscle Biopsy: A Practical Approach )/ Do you like it?

By the way, if you are still following my blog, you would know we were in Springfield recently, but I didn't think to give you a call.

I also plan on leaving Loyola and moving on to the Advocate group in Chicago, in August.

Brian E. Moore, MD said...

I would have enjoyed meeting you when you visited in Springfield. Please give me a call next time you’re in town! Regarding the Dubowitz book, I do own that and I like it. There is no really good muscle biopsy book, but I think that Dubowitz 3rd edition is the best that is out there.

jd said...

Dubowitz is OK, but I like Carpenter/Karpati is better. I use both.

Jean said...

Hi just had surgery for CVA tumor removal last Tues. In hospital no beta 2 test why don't they just check. It is hard to even know what is going on regarding taste or dripping following long difficult surgery. Now I felt slight drip clear down other side nostril a few times after eating. Impossible to say norm secretion or what. Also have gross enzymy not really metallic taste in mouth. Will call doc today anyway but just curious local lab do beta? Pharmacy has? Thanks so much, Jean

Hans said...

"Beta-2 transferrin is alternatively known as tau protein (the same tau, in a hyperphosphorylated form, which makes up the tangles of Alzheimer disease). Beta-2 transferin is a type of microtubule-associated protein (MAP), which is a protein that binds and regulates the stability of cytoskeletal filaments."

I believe that this is INCORRECT, i.e 2 different proteins have been conflated here!

Tau protein is the product of the MAPT gene located on human chromosome 17.

Beta-2 transferrin is the product of the TF gene located on human chromosome 3.
The TF gene produces beta-1 transferrin, which is desialated in the CNS to beta-2 transferrin.

Brian E. Moore, MD said...

Thanks for correcting that error, Hans. I suspect that one of my sources, perhaps Tietz Clinical Guide to Laboratory Tests, had it wrong. Or, I may have misinterpreted what I read. Either way, by the time you read this comment, the blog entry will be changed so as not to conflate these two distinct proteins. Thank you for your close attention, Hans!