< Actual value is known to be less than or equal to the value shown. > Actual value is known to be greater than or equal to the value shown. A Mean value. D Biological organism count equal to or greater than 15 percent. E Estimated value. K Results based a nonideal colony count (outside the acceptance range). M Presence of material verified, but not quantified. N Presumptive evidence of presence of material. S Most probable value. U Material analyzed for but not detected.