Antech Diagnostics does not recommend the use of gray top blood collection tubes to stabilize blood glucose. The sodium fluoride preservative contained in these tubes is formulated to stop red cell metabolism and prevent the in vitro consumption of blood glucose. However, it has been determined that the same preservative will also inhibit the enzymatic test reagent used in glucose assays, causing falsely low glucose measurements. This problem is especially evident when the gray top tube is only partially filled, resulting in a high concentration of the sodium-fluoride preservative within the blood sample.

The preferred sample for blood glucose, and all constituents of the Chemistry Profile, is a Serum Separator Tube (SST) that contains an inert gel to separate the clot and blood cells from the serum. After collection into an SST, the blood should be allowed to clot for 10-30 minutes and then be centrifuged for 3-10 minutes. If your facility needs a centrifuge for processing laboratory specimens, please contact your Antech Client Service Representative for information on the purchase of a low cost instrument.