Herpes Simplex Virus(HSV) 1 & 2 IgM test helps in early diagnosis of the highly contagious Herpes disease caused by HSV. In general HSV-1 causes oral herpes, indicating symptoms like cold sores and blisters near the mouth or on the face. While HSV-2 causes genital herpes, which is manifested by sores in the genital area. Other symptoms of the HSV 1 and 2 infection include fever, sore throat, headache, and tingling in the affected area. This test is also suggested in case of encephalitis where the viral infection is suspected.