- 1-11 months of age must have > 2000 cells/mm3 and >= 30 percent of the total lymphocytes; 12-23 months must have > 1000 cells/mm3 and >= 20 percent of the total lymphocytes; 24 months-6 years must have > 750 cells/mm3 and >= 20 percent of the total lymphocytes; and 7 years and older must have > 500 cells/mm3 and >= 20 percent of the total lymphocytes.