Creatine kinase (CK) is a dimeric that has got four different forms. They are CK-MB (mostly present in the heart muscles), CK-BB ( mostly present in the brain), CK-MM (mostly present in the muscles), and mitochondrial isoenzymes. CK-MB can be measured by the immunoinhibition method.
CK-MB Normal Range
The normal range of the CK-MB can depend upon numerous factors. It depends upon the method of measurement or the reagents used for the measurement in the laboratory.
In normal cases, creatine kinase is not present in the blood. In other words, the concentration of CK-MB in the serum measured at 37°C in the laboratory will not be more than 24 units per liter.
If the concentration of CK-MB goes above this, then that means you may be suspected of different kinds of diseases such as acute myocardial infarction(commonly known as a heart attack), stroke, rhabdomyolysis, etc. At the onset of these diseases, CK-MB will be detected in the blood after 4-8 hours. Then after 12- 24 hrs, its concentration will be at the peak. Finally, after 3 days, it will come back to its normal level. Thus, the time when a blood sample from the patient is measured can also alter the value of CK-MB to some extent.
CK-MB Vs Troponin Vs Myoglobin
All of the three enzymes (CK-MB, Troponin, and Myoglobin) are known as cardiac markers. In other words, they are all used to treat patients with heart diseases. However, there are few differences between those three markers. For more details about the cardiac markers, please go through the video shown below.
CK-MB Immunoinhibition Method
1. Principle Reaction
CK-M antibody inhibits the CK-M fraction of CK-MM and CK-MB activity (the main part of the total CK activity). Then only the CK-B portion is measured. Then CK-MB is calculated by multiplying the value of CK-B activity by 2.
2. Sample Preparation
The table shown below for CK-MB measurement is valid for Tulip, Accurex, Analyticon, and Diasys Companies. So, if you have the reagent kit of any other company, then there can be minor fluctuation in the method.
If you have two reagents, then make a working solution out of them. The ratio of their composition will be given in the literature of your reagent kit or the reagent bottle. Else, a single reagent can also be found based on the company. In that case, that single reagent kit will act as a working solution for you.
If you need to do any external incubation, then you can use an incubator or dry bath. Also, if you need to make a reagent blank then, replace the sample/calibrator with the same volume of distilled water and mix with the working reagent.
Always remember that sipping volume < sample volume + reagent volume. So that means, make sufficient sample volume to feed into the semi-auto biochemistry analyzer. Else, it will suck up the air and will give the fault reading.
If the concentration of CK-MB is too high (out of range/ non-linear), then dilute the sample with 0.9% NaCl or distilled water at the ratio of 1:y. Finally, when you get the result, multiply the value with the dilution factor (1+y).
3. Programming of CK-MB in a Semi-auto Biochemistry Analyzer (Immunoinhibition Method)
4. Handling of CK-MB Reagents
- Wear an apron and surgical gloves before carrying out the measurement.
- Look for the expiry date of the reagents during purchase and measurement time. Suppliers tend to give you reagent kits with a low expiry interval.
- Once you open the reagent bottles, the lifespan will decrease. So, look in your reagent kit literature for that.
- Bring the reagents and samples to room temperature before you can carry out any measurement.
- Always store reagents in the refrigerator when not in use.