The GHB determination methods applied in clinical laboratories are mainly classified into two categories:
One is based on the difference in charge between GHB and non-GHB, such as ion-exchange chromatography, electrophoresis and isoelectric aggregation methods
The second is based on the structural characteristics of the glycation groups on hemoglobin, such as affinity chromatography and immunoassay
(1) Affinity chromatography: this method is highly specific , which is not interfered by abnormal hemoglobin. It is suitable for use in clinical departments and is especially advantageous for pediatric patients. Its test results also fully meet and exceed the clinical requirements, with a CV value of 5% or less. NycoCard READER II, a Norwegian small cyclone glycated hemoglobin meter from ZTE (Beijing) Trading Company, is the representative.
(2) High Pressure Liquid Chromatography (HPLC) can fully automate the separation and determination of glycated hemoglobin and blood protein variants and subtypes, but the operation and maintenance of the instrument requires high CV value of 1% or less. It is represented by HLC-723 G7 of Beijing Deaconess Medical Corporation.
(3) Immunoagglutination: The principle is that glycated hemoglobin binds to the corresponding monoclonal antibody and then agglutination reaction occurs, and the amount of agglutination is expressed by measuring the absorbance, which can be used in automatic biochemical analyzers for measurement. A new kit should be used for each test, and care should be taken to mix the reagents before handling. It is pointed out that the immunoagglutination method for the determination of glycated hemoglobin has poor precision, and the CV value is generally not 5%. DCA Vantage of Zhongyi Kanghui (Beijing) Trading Co.
(4) Ion capture method, the principle is that glycated hemoglobin and the corresponding antibody binding, linked to fluorescent markers, and in the IMX reaction hole in the glass fiber pre-coated with polymer tetramer, so that the fiber surface is positively charged, so that the reaction complex adsorbed on the surface of the fiber, after a series of cleaning and measurement of fluorescence intensity, so as to get the concentration of glycated hemoglobin, the method is suitable for batch glycated hemoglobin. The method is suitable for the detection of batch glycated hemoglobin specimens. The IMX of Beijing Southeast Chemistry is the representative
(5) Electrophoresis: Capillary electrophoresis can also separate and detect glycosylated hemoglobin and hemoglobin plasma variants, but there is no commercialized instrument with the ability to pass batch samples, which limits the clinical application of this method to a considerable extent.