Liver function tests require fasting blood draws. This is because normal human blood contains a certain amount of large-molecule beta and gamma globulins that can precipitate by combining with certain chemical reagents, while small-molecule albumin and alpha1-globulins, prevent precipitation. Therefore, when the prescribed chemical reagents are added to normal human serum, no precipitation or slight precipitation occurs due to the inhibitory effect of albumin. In hepatitis patients, due to the decrease of albumin and increase of beta and gamma globulins in the serum, significant precipitation occurs after the addition of chemical reagents in their serum. The composition of the serum is changed after eating, and precipitation of varying degrees occurs even in normal human serum after the addition of chemical reagents. The precipitation occurs more obviously especially when high protein or high fat foods are consumed. The reported results can easily misdiagnose a normal person as a hepatitis patient. For accurate results, blood should be drawn on an empty stomach for liver function tests.