From the Research
Testing for GLP-1 in the blood requires an ultrasensitive method, such as immunoaffinity LC-MS/MS, to accurately measure active and inactive GLP-1 levels. This is because GLP-1 circulates in many different forms, some of which are biologically active and others are not, and various methods to measure GLP-1 detect different forms of GLP-1, which may cause confusion when comparing results 1. To get tested, you'll need a healthcare provider to order the test, which usually involves a fasting blood draw in the morning. It's essential to follow pre-test instructions, which often include fasting for 8-12 hours before the blood draw. The blood sample must be collected in specific tubes containing protease inhibitors and DPP-4 inhibitors to prevent GLP-1 degradation, and the sample needs to be processed quickly and kept cold.
Some key points to consider when testing for GLP-1 include:
- The sensitivity and specificity of commercially available kits for the analysis of GLP-1 levels vary considerably, and this should be taken into account when selecting which assay to use and when comparing data from different studies 2.
- The pattern of postprandial GLP-1 responses in clinical samples can be similar between different kits, but the absolute concentrations measured can vary 2.
- GLP-1 testing isn't routinely performed in standard clinical practice but is more common in research settings or specialized endocrinology practices.
- The test measures active GLP-1 levels, which are important in glucose metabolism and insulin secretion.
According to the most recent and highest quality study, an ultrasensitive method for the quantitation of active and inactive GLP-1 in human plasma via immunoaffinity LC-MS/MS is the most accurate way to measure GLP-1 levels 3. This method has been shown to be more sensitive and selective than other commercially available assays, and it can be used to qualify and/or harmonize the different immunoassays used for the quantitation of GLP-1.