Set the parameters of automatic biochemical analyzer

Analysis of 1 common analysis methods are: end-point analysis, continuous monitoring method, turbidimetric assay.
Characteristics of the
1.1 endpoint analysis
1.1.1 point terminal method this method is the use of one or two kinds of reagents, absorbance was measured to be determined to reach the finish material and reagent reaction time, concentration of analyte, calculation. The method is common with biuret method, total protein albumin by bromocresol green method, glucose oxidase method. The
1.1.2 method also known as two end fixed time method. In the single reagent analysis, this method can eliminate the interference of sample and reagent color, turbidity, its principle is to read a little A1 at the lag phase sample and reagent after mixing, after a certain time to read A2, Δ A=A2-A1, Δ A standard and then compared to measured value, the concentration of analyte. Analysis of common single reagent with creatinine picrate method. In the double reagent analysis, the method has to eliminate the interference of endogenous substances determination, the principle is added after 1 read A1, added 2 after reading A2, A1 is equivalent to read the sample blank value, A2 is the actual color reaction, so Delta A=A2-A

1.2 continuous monitoring method and its principle is the most suitable conditions in enzymatic reactions, methods of analysis for physical, chemical or enzymatic reaction, reaction rate constant (in period zero level reaction period) to continuous observation and recording of changes in substrate or product to a certain amount of reaction time, initial velocity of enzymatic reaction in unit time calculation the concentration of the value of enzyme activity and metabolite. The specific method for two rate method and multi-point rate method.
1.2.1 points rate observed in the zero level reaction period two time points of the absorbance, with the difference absorbance of two points (Δ A) divided by time (points), calculated the value of absorbance change per minute. Zero level reaction period
1.2.2 multipoint rate method to promote the reaction process in enzyme every definite time (2-30s) a monitoring, continuous monitoring for many times, the reaction rate per unit of time

1.3 nephelometry automatic biochemical analyzer can only do turbidimetric analysis of transmission, the principle is in the optical path direction of light through the light intensity measurement, it is often used for endpoint assay, the mostly used as immune turbidimetry. At present is mainly used for the detection of serum specific protein, such as apolipoprotein, trace protein, acute phase proteins, immunoglobulins and some drug monitoring etc..

2 the temperature controller for general biochemical analyzer can be constant temperature of 25 ℃, 30 ℃, 37 ℃ three temperature, according to need can be arbitrary choice. Due to the enzyme in the optimum temperature, temperature rise every 10 ℃, the reaction rate increased 1-2 times, so the IFCC is recommended to set the temperature at 37 ℃ enzyme assay.

3 wavelength of
3.1 single wavelength when the assay system containing a component or a test component of the absorption peak wavelength and other coexisting substances without overlapping in the mixed solution, can choose. If a substance has several absorption peaks, can choose a wavelength absorbance maximum, or choose from the absorption peak of absorbance at wavelength of less a wavelength.
3.2 dual wavelength when interfering substances. The turbidity of the solution or the presence of more, light scattering and non-specific absorption will be determined, thus affecting the accuracy of the result, this time by double wavelength determination, to improve the accuracy of measuring results, and selection in the practical application of auxiliary wavelength is mainly used for interference cancellation lipemia, hemolysis, jaundice. Because of lipid, bilirubin, hemoglobin is strong light absorption in a wide wavelength range, often with the detection wavelength overlap, the absorbance measured at this time included the absorbance analyte absorbance and interfering substances, therefore selected wavelength absorbance suitable can eliminate the interferent matter. The setting principle of auxiliary wavelengths are determined according to wavelength selection of auxiliary wavelength, requirements of interfering substances in determining wavelength with auxiliary wavelength have the same absorbance.

4.The setting principle of sample and reagent amount of sample and reagent volume is generally based on the proportion of kit, and combined with the characteristics of the instrument set. The instrument features: the minimum sample volume of sample and reagent and dosage range, minimum reaction liquid volume. In practical work to save costs can be reduced according to the proportion of sample and reagent consumption, but also must meet the minimum amount of reaction liquid. But it is worth noting, sample volume should not be less than 3 μ L, repetitive or test result difference

5.dilution water adding sample dilution water to wash out the adhesion in the sampling needle on the inner wall of the trace serum, reduce the sampling errors, add reagent dilution water to avoid cross contamination between reagents, two kinds of dilution water amount should be deducted according to the ratio of dissolved reagent. As with a liquid reagent kit with no water, no deduction of dilution water, so the two kinds of dilution water quantity should be reduced as much as possible, in order to ELISA were excessive dilution.

6.The incubation time in the final analysis, the incubation time selection should take full account of the interference problem. In the albumin by bromocresol green method, the serum α 1- globulin, transferrin, haptoglobin, also with bromocresol green color, but the reaction rate is slow compared to albumin, and in fact, when the serum albumin and mixed, "slow" has occurred, thus significantly reduce non-specific binding reaction in Xiu Jiafen green and serum after mixing with 30s read absorbance. In the method of glucose oxidase, glucose oxidase specific catalytic beta -D- glucose, and glucose in serum alpha and beta configuration each accounted for 36% and 64%, in order to make glucose reaction, must extend the incubation time of the alpha to beta configuration glucose mutarotation. In addition, Trinder enzyme reaction method using total cholesterol, triglyceride were measured, but the reaction at 37 ℃ slow reaction, must be determined to reach the end of the time of these enzyme reagent kit for automatic analyzer, generally in the reaction of 5min in all samples, the maximum response time to should choose analyzer

7.The delay time in the enzymatic reaction of a starting stage, due to the influence of various factors, the enzymatic reaction rate is slow, can be a few seconds to several minutes, especially double substrate reaction or coenzyme participants, usually 1-3min. While the general single reagent method only needs 30s, enzyme, aspartate aminotransferase, creatine kinase, the need to pay particular attention to alanine aminotransferase of commonly used project.

8.Monitoring the time of enzymatic reaction lag phase, in the presence of excess substrate, the reaction rate and reaction rate reached a stable stage, namely enzymatic reactions proceed at a constant rate, are not affected by the concentration of substrate, this paragraph of time is called linear reaction period or zero level reaction time, monitoring time automatic biochemical analyzer of this period. The continuous monitoring method of measuring the enzyme at least 90-120s or at least 4 points (3 A), less than 3 A can not be called continuous monitoring method, because the linear computation cannot. Long monitoring time is prone to substrate exhaustion, can be measured.

9.Upper limit, lower limit of reagent absorbance of reagent absorbance limit of positive reaction, can reference kit brochures numerical converted into the cuvette optical path. Such as kit request limit is 0.4, colorimetric cup light diameter 0.8cm, the reagent absorbance limit is set to 0.32. Reagent absorbance limit of negative reaction, setting method and reagent absorbance limit. Exceed the limit indicated reagent has been bad, should replace eligible reagent.

10.The substrate depletion quota design different types of analyzers are not the same, some for the zero balance and monitoring the first point absorbance, and some numerical absorbance rise or fall to the specified absorbance. Exceed the limit that enzyme activity of samples is very high, substrate consumption too fast, the change in absorbance in the linear response within the specified period instrument procedures often do not represent the enzyme activity of real, resulting in a low, the samples should be diluted 5-10 times after the retest.

Set the parameters of automatic biochemical analyzer

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