Need help knowing what this lab value is supposed to be.

[BabyLady, BSN, RN]

for one of our nursing projects, we have to list all abnormal lab values and tell what the lab is run for, what the normal values should have been, and list our patient's lab values.

for some reason, there is one that i cannot interpret. my patient was admitted to the er with a possible stroke.

the lab page is short....so i'll list what was on it, and i'll highlight in red what i'm looking for...i just need to know what it's for.

special chemistry: (all labs that were ordered were ck, mb & index, troponin tn 1)

cpk abnormally low: 31 normal range: 33-187 u/l

ck-mb normal: 2.6 normal range: 1.58 - 6.85 ng/ml

relative & index of ckmb

abnormally high: 8.4 normal range: 0.0 - 3.0%

i cannot figure out what this is from an internet search, my lab book, nothing.

i know that the cpk measures creatine phosphokinase...and when it's high, it is indicative of injury to the heart, brain or muscle tissue and used to dx a heart attack.

however i have no idea of what "relative & index of ckmg" lab means, or what it's supposed to be a percentage of.

thanks!

[hypocaffeinemia, BSN, RN]

A typical CK-MB level is the absolute level of CK-MB.

The relative level of CK-MB is the percentage of M and B types to all CPK.

This is important, because typiclly CK-MB makes up a very small percentage of total CPK (

Your skeletal muscle only has a tiny amount of CK-MB, it's mostly CK-MM.

Meanwhile, your cardiac muscle has a higher percentage of CK-MB, which makes an elevated level more specific to cardiac muscle damage.

[BabyLady, BSN, RN]

Thanks...so (and I'm presenting this as a question to make sure I understood your post correctly)...if the % is high, then that is indicative of relatively recent heart damage? Or is it another diagnostic too...that doesn't definitively diagnose, but just a tool that may indicate, but not prove a recent heart attack?

Thanks!

[hypocaffeinemia, BSN, RN]

Thanks...so (and I'm presenting this as a question to make sure I understood your post correctly)...if the % is high, then that is indicative of relatively recent heart damage? Or is it another diagnostic too...that doesn't definitively diagnose, but just a tool that may indicate, but not prove a recent heart attack?

Thanks!

To be honest, I don't know. While a high percentage of CK-MB to total CPK might be a useful diagnostic in a situation where both were elevated and you are attempting to rule out cardiac versus renal failure versus rhabdomyolysis, I don't think it is as specific, as sensitive, or as early-detected as troponins would be. In my limited experience, I've never seen the relative percentage ordered or reported-- though it isn't hard to figure out: (CK-MB / CPK ) * 100.

[BabyLady, BSN, RN]

Ok...that tells me what I need to know...thank you so much.

We go to so many different facilities, and it's impossible to know how to read the labwork at each one because for some labs they use different abbreviations, etc, and of course, I don't have enough experience to really figure it out on my own.

So I'll probably put as an explanation for the test as, "Adjunct diagnostic tool to assess cardiac muscle damage."

Your math is better than mine b/c I never would have figured out that formula on my own.

I figure heck, if I'm wrong, I can't be THAT far off....

[morte, LPN, LVN]

http://www.diagnosticsample.com/point-of-care/analytes.php?base=biochemistry&id=61&broj=6&lang=en&idqds=0

[hypocaffeinemia, BSN, RN]

Good link, morte.

[morte, LPN, LVN]

why, thank you, suh!

lol....just searched on the term....relative+index+ckmb........it came back and aske if i meant there to be a space between ck and mb....clicked on that and away we went!

[BabyLady, BSN, RN]

THANK YOU MORTE!!!

[morte, LPN, LVN]

THANK YOU MORTE!!!

well, gosh.....you're most welcome ma'am....lol.....i didnt read much, maybe it is worth a bookmark, for further reference? other lab work etc?