CKMB ratio - page 2

I have been searching/surfing for the formula to figure the CKMB ratio and can't find it. What should it be to indicate non-MI and when do we begin to suspect MI ? I have had patients with normal... Read More

  1. by   critcarenurse16
    [QUOTE=Angie O'Plasty, RN]OK Folks, I think I've got it--and thanks for the question that led me to search, because I did learn something interesting and valuable.

    An excerpt from CK-MB, The Test:
    CK-MB levels, along with total CK, are tested in persons who have chest pain to diagnose whether they have had a heart attack. Since a high total CK could indicate damage to either the heart or other muscles, a high CK-MB suggests that the damage was to heart muscle. If your doctor thinks you have had a heart attack and gives you a "clot-busting" drug (called a thrombolytic), CK-MB can help your doctor tell if the drug worked. When the clot is broken open, CK-MB tends to rise and fall faster. By measuring CK-MB in blood several times, your doctor can usually tell whether the drug has worked.

    ...If the ratio of CK-MB to total CK (relative index) is more than 2.5-3, the heart is the likely muscle damaged. A high CK with a very low relative index suggests that other muscles were damaged.

    ...Severe injury to skeletal muscle can be significant enough to raise CK-MB levels above normal, but such injury doesn't usually cause a high relative index. If your doctor suspects injury to both heart muscle and skeletal muscle, it may be hard to detect heart injury. Then your doctor may need to order other tests (such as troponin).

    ...Sometimes persons who are having trouble breathing have to use their chest muscles. Chest muscles have more CK-MB than other muscles, which would raise the amount of CK-MB in the blood.

    ...Persons whose kidneys have failed can also have high CK-MB levels without having had a heart attack. Rarely, chronic muscle disease, low thyroid hormone levels, and alcohol abuse can increase CK-MB,

    Thanks for keeping it simple--I feel my understanding has been enhanced. I was beginning to question what I thought to be true of CK/CKMB%
  2. by   TLC_RN_BSN
    Here it is:

    MB/CPK=......X 100= R.I.(Relative Index aka ratio)

    Our positive ratio is >3.5

  3. by   NorthER,RN
    Thank you all very much. In my little hospital we use Troponin T markers which are not as accurate as Trop I which I am used to. I wanted to learn more about CK/CKMB ratios and now I have thanks to you. You'll make me look good! Thanks.