Common automatic biochemical analyzer detection methods are: endpoint method, kinetic method, immunoturbidimetry, fixed time method, double reagent method, etc. What is the specific meaning? Let's take a brief introduction below, and don't ask for in-depth research, just ask for some understanding and difference.
End point method: When the reaction reaches the end point, that is, when the absorbance does not change on the time-absorbance curve, an end point absorbance value is selected for the calculation result.
The calculation formula of the result: the concentration of the analyte to be measured CU = (the absorbance to be measured AU - the reagent blank absorbance AB) × K.
K is the calibration factor.
Kinetic method (ie continuous monitoring method, rate method)
: Also known as the rate method, when measuring the enzyme activity or enzymatically measuring the metabolite, continuously select the absorbance value of the linear phase (the difference in absorbance between the two points is equal) in the time-absorbance curve, and the unit of the linear period Absorbance change value calculation result.
Immunoturbidimetric method: When light passes through a turbid medium solution, the light is absorbed by a part of the turbid particles in the solution, and the absorption is proportional to the amount of the turbid particles. This method of measuring the light absorption is called transmission turbidity. law.
Fixed time method (two-point method): refers to selecting two photometric points on the time-absorbance curve. These two points are neither the reaction initial absorbance nor the end absorbance. The absorbance difference between the two points is used for the result calculation, sometimes Call this method a two-point method.
The calculation formula is: CU=(A2-A1)×K.
Double reagent method:
Liquid Single Reagent: The reagents used in a biochemical test project are scientifically mixed together and combined into one reagent.
When applying, it is only necessary to mix the test specimen and the reagent in a certain ratio, and then the corresponding biochemical reaction can be carried out, and then the result is detected by an appropriate method.
Liquid double reagent: The reagents used in some biochemical test items are scientifically divided into two categories according to their uses, and they are respectively formulated into two kinds of reagents.
Usually, after the first reagent is added, it can completely or partially eliminate some of the endogenous interference.
The second reagent is a reagent that initiates a reaction of the substance to be detected.
After the two reagents are mixed, the biochemical reaction of the tested item is completed together, and then the result is detected by an appropriate method.
The single reagent has the characteristics of poor anti-interference ability, which will bring analysis error.
The accuracy of the two reagents is high, which eliminates the endogenous interference of the sample. In the end point test, the influence of factors such as blank (heavy turbidity, hemolysis, jaundice, etc.) and cuvette can be eliminated, and the measurement is improved. Accuracy, and reagent stability: Reagent 1 (R1), reagent 2 (R2) are stored separately, which improves the stability of the reagent.
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