Commercial out saying that clearblue easy pregnant tests that tell you how far along you are are as accurate as ultrasound. is this true? how can that be?

With limitations...: All pregnancy tests measure the presence of a hormone called hcg. A test is positive, if it's present in your urine or blood. You can measure how much of this hormone is there, and use the number to est. How long it has been since ovulation, i.e., to date a pregnancy. But, the number begins to vary quite a bit after about 3 wks, so the test only works for this in the earliest stages.

Marketing: I think this is all about marketing and doubt the accuracy of the claim once you are past about three weeks since impregnation. I do not believe this test would be better or as accurate as the early ultrasounds are for dating purposes. I also wonder if the information this test claims to offer is worth the extra charge for the product.