Test Catalog Search Home Test Catalog Search Testing Choices: From the standard to the extraordinary × Search Clear Filter by: Clear all Method(s) Spectrophotometry (SP) (1) Sample Type Blood (2) Fluid (1) (-) RBCs (1) Serum or Plasma (2) Tissue (1) Urine (1) Test Area (-) Exposure (1) Test Category (-) Biomarkers (1) Metals/Elements (1) Test Sub-Category Other (1) Test Test Name 4235R Sulfhemoglobin, RBCs