Clinical Chemistry, Vol 37, 1683-1687, Copyright © 1991 by American Association for Clinical Chemistry

Determination of silver in blood, urine, and tissues of volunteers and burn patients

AT Wan, RA Conyers, CJ Coombs and JP Masterton
Department of Biochemistry, Alfred Hospital, Melbourne, Victoria, Australia.

Silver sulfadiazine cream (SSD) has been used successfully in the management of burn wound sepsis. Silver deposition has been found in the skin, gingiva, cornea, liver, and kidney of patients treated with this cream, causing argyria, ocular injury, leukopenia, and toxicity in kidney, liver, and neurologic tissues. Monitoring concentrations of silver in blood and urine of patients receiving this treatment has become necessary, but sensitive and suitable methods adaptable to a clinical laboratory are still needed. We have developed a flameless thermal atomic absorption spectrophotometric method to measure silver concentrations in blood, urine, and other tissues. The detection limit is 0.4 microgram/L; the within-run precisions (CV) are 5.16%, 3.83%, and 2.79% for concentrations of 5, 13.5, and 42 micrograms/L, respectively; and the between-run precisions are 4.3% and 3.2% for concentrations of 13.5 and 42 micrograms/L. The concentrations of silver in blood, urine, liver, and kidney of subjects without industrial or medicinal exposure are less than 2.3 micrograms/L, 2 micrograms/day, 0.05 microgram/g wet tissue, and 0.05 microgram/g wet tissue, respectively. In SSD cream-treated burn patients, plasma concentrations may be as great as 50 micrograms/L within 6 h of treatment and can reach a maximum of 310 micrograms/L. Silver in urine is detectable after one day of treatment and may reach a maximum of 400 micrograms/day. After absorption, silver was found to be deposited in various tissues. Tissue silver concentrations in one burn patient who died of renal failure after eight days of treatment were 970, 14, and 0.2 micrograms/g wet tissue in cornea, liver, and kidney, respectively.