Although there were significant increase in levels of N%, DD, ALT, BUN, Mb, ESR, CRP, and PCT and significant decrease in levels of L%, L, Pt, Hb, and albumin in old age group, the majority of these values were still in the normal limit of reference, suggesting subtle and subclinical changes of many blood lab tests occur with severe or critical type of infection. Here, ESR1 is linked to infection.