Inform your doctor if you are on any medications, have any allergies or underlying medical conditions before your Immunoglobulin Igg Synthesis Index & Rate Bcg, Nephelometry, Immunoturbidimetry Blood Serum. Your doctor will give specific instructions depending on your condition on how to prepare for Immunoglobulin Igg Synthesis Index & Rate Bcg, Nephelometry, Immunoturbidimetry Blood Serum.