I have become very prone to fungal & viral infection. Can you suggest which type of immunity test should I undergo to check it's strength?

Vague comments. Without knowing exactly what you have had and the frequency your fears may or may not be valid. What would be best would be to go to your family doctor (internist, family practitioner) and let them get a full history and do a physical exam and perhaps some labs and/or imaging studies. If you have been exposed to HIV this can also be tested for.

Related Questions

I have become very prone to fungal & viral infection. Can you suggest which type of immunity test should be done to check it's strength?

More info needed. How long has it been going on? Since you were a child or in the last several months? ----> If in the last several months or few years, start with an HIV test. ----> If since childhood, then it is more complicated to discuss here.

I have become very prone to fungal & viral infection. Can you suggest which type of immunity test should be done to check immune sytem's strength.?

See the doctor. If you are concerned see the doctor and have an assessment of what is going on with you and what tests would be best. Possibly best to be seen by an Infectious Disease doctor.

I have become prone to fungal & viral infection. Can you suggest which type of immunity test should be done to check immunity strength like igg1, etc.

See Immunologist. As a generality, T-cell dysfunction (and not B-cell or lack of antibody production) could potentially lead to susceptibility for viral and fungal infections. One might start by checking lymphocyte subpopulations and T-cell function as an initial work-up.
Not just a test. But an evaluation by an experienced immunologist, you might not have a primary immune deficiency, may be just a transit condition causing secondary immune deficiency due to a drug or virus infection, so history, drug history, physical examination are important for evaluation, look for an expert in the field, meanwhile check cbcd, total IgG, IgE, IgA & IgM, + T&B lymphocytes flowcytometry,