Couple of days back I bought a pulse oximeter Dr. Trust brand and started checking my oxygen levels. In the mornings it is 97 -98 % but after noon it starts going down to 95 % sometimes even 94 % is that ok ? One more thing - it displays a value called RI % (it ranges from 2 to 25 approx and changes second to second ) Can somebody please explain. Is SPO2 of 95 % ok for a cfs patient ? Thanks in advance.