There is no established BEI for blood chromium. The general population ranges for blood or serum chromium are about 10 times lower that the ranges for urine levels. To measure these levels at such low concentrations, great care must be taken by the lab and the sample collector to avoid contamination. Virtually all venipuncture is performed with stainless steel needles. We have been involved in high level studies for chromium exposure where we have performed the phlebotomy via Teflon IV cannulas.
Blood is drawn into plastic syringes and placed inside metal free tubes.
It is a lot of trouble for routine monitoring. For a variety of reasons urine is the matrix of choice for routine biological monitoring of chromium workers, although blood determination holds promise. I'll send you a copy. Chromium picolinate is being taken daily by millions of Americans, spurred by advertising claims that the substance'' fosters weight loss, promotes muscle growth, diminishes body fat and may even lengthen life''. He put up a sign on the door to the clinic that informed the patients that they were exposed to carcinogens and that they should please not bring any of the carcinogens into his clinic but protect themselves too.