Recent information has suggested that mega doses of biotin (5,000-10,000 mcg or more) may interfere with some lab tests, so several national lab testing services recommend ceasing supplementation with mega doses of biotin starting two days prior to certain lab tests. The mega-dose amounts are 166 to 333 times higher than the amount of biotin in Qualia Skin (or other Qualia products that have biotin as an ingredient). While the amount of biotin in Qualia Skin would not be expected to cause interference in lab tests, it is a good idea to let your doctor know you are taking a supplement with biotin and follow any recommendation they may have about stopping it prior to lab testing.