Yours mother tested by which test antigen or rtpcr, oximeter should read after 1 -2 minute after applying in index or middle finger, it will be correct reading. If spo2 come below 94% it needs urgent action. You can go for blood test -cbc ese, pct , d dimer, ldh, serum
ferritin level, hrct chest. to confirm the diagnosis.
Next Steps
if spo2 below 94% take Consultation with Physician.
Health Tips
you can consult me on Practo app