I drink quite heavily and i'm due for a alcohol blood test in two weeks time. how long will it take for it to be clear on test?

Quickly: Once you are sober your levels of alcohol will be zero. However, you may fool the test but you cannot fool mother nature. If you are drinking too much you will end up paying for this one way or the other. Your liver tests if abnormal can be elevated for weeks.

Depends/ metabolism: In the average individual, 1/2 of the existing ethanol will be out of the system in about 1/2 hour, but this is effected both by loading (continuing to drink) & the livers ability to metabolize the product.If your liver cannot remove the product as fast, it stays longer.Abstaining for at least a day should clear most, but longer may be needed.