The lactate dehydrogenase enzyme (LDH enzyme) consists of five different isoenzymes. These isoenzymes differ slightly in structure and are found in different parts of the human body. LDH enzyme is mostly present in the liver, heart, and skeletal muscle. A small amount of lactate dehydrogenase is also present in erythrocytes, pancreas, kidney, and stomach. The measurement of this enzyme is possible by a DGKC method in a semi-auto biochemistry analyzer.
Lactate Dehydrogenase Normal Range
The normal range of the lactate dehydrogenase shown below is the approximate value. So, there can be minor variations in the range set by the laboratories due to the method of testing, reagents used, etc. Besides that, geographical location, habitat, age, sex, etc, can also alter the value.
- Men:- 135 – 225 Units per liter
- Women:- 135 – 214 Units per liter
- Children (2-15 yrs):- 120 – 200 Units per liter
- Neonates (4 – 20 days):- 225 – 600 Units per liter
An elevation of LDH can be an indication of myocardial infarction, cancer, and diseases of the liver, blood, or muscle.
DGKC Method for Lactate Dehydrogenase Measurement
1. Principle Reaction
Lactate dehydrogenase (LDH enzyme) catalyzes the reduction of pyruvate by NADH to form lactate and NAD+. The rate of conversion is directly proportional to the LDH enzyme.
2. Sample Preparation
The table shown below for lactate dehydrogenase measurement is valid for the reagents of 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.
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 lactate dehydrogenase 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 Lactate Dehydrogenase for a Semi-auto Biochemistry Analyzer (DGKC Method)
4. Handling of Lactate Dehydrogenase 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.