At least one group has taken a hard look at nano-nutraceuticals to determine whether they might impact typical blood and urine tests.  The writers note that 1/3 of American consume some sort of diet supplement including several "nano-based" products.  They further note "the oral administration of metallic colloids, in particular colloidal silver protein, has been reported to have toxic effects.”  The writers tested certain nanoscale metal colloids to see if they interfered with clinical blood and urine tests.  The writers found “nanoparticle nutraceuticals exhibited no major interference with the tests examined.”  However, they cautioned “[c]linical laboratories should remain vigilant for possible nanoparticle interferences, as these structures, with their diverse physical and chemical properties, are being used or advocated for use in a broad range of drug delivery applications and as imaging agents.”

J. Park, et al., Letter to the Editor “Nanotechnologic Nutraceuticals: Nurturing or Nefarious?” Clinical Chemistry 52, No. 2 (2006).