Getting the best results from your lab tests

Fasting instructions:

  • Overnight fast. Please fast for at least 12 hours. This means you should not eat or drink anything including coffee after 9 PM. Water is ok.
  • Drink plenty of water to make the procedure easier.
  • Complete lab test by 9 AM.
  • Take all prescription medications as usual unless otherwise instructed.
  • Do not smoke, chew gum, or exercise, as these activities may stimulate the digestive system and alter the test results.

Special instructions:

Biotin supplements specifically marketed for hair, skin, and nail growth contain up to 10-30mg of biotin.

  • Your lab results may be affected and incorrect test results may be generated if you are taking a biotin supplement.
  • TSH, FT3, and FT4 that we order routinely in our clinic can be affected by biotin supplements.
  • Usually multivitamins have a biotin level of less than 500mcg and should not affect the lab test.
  • Accurate lab results can be obtained by discontinuing biotin supplements two days prior to the lab test.

Center for Obesity Medicine & Metabolic Performance

6700 West Loop South, Suite 500 • Bellaire, TX 77401 • 713.486.1330

11920 Astoria Blvd, Suite 460 • Houston, TX 77089 • 713.486.7650

17510 W. Grand Parkway South, Suite 450 • Sugarland, TX 77479 • 713.486.3950