LOW CD4+CELLS TEST RESULT REFERENT VALUES FOR ADULT. What does low CD4+ cells test result referent values for adult level mean?

Lower limit of normal CD4+ cells test result referent values for adult is 0.4( x10^9/L)

CD4 is a glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells.

Low CD4+ cells are associated with a variety of conditions, including many viral infections, bacterial infections, parasitic infections, sepsis, tuberculosis, coccidioidomycosis, burns, trauma, intravenous injections of foreign proteins, malnutrition, over-exercising, pregnancy, normal daily variation, psychological stress, and social isolation.