It is important to have a clinical correlation of the test results.CKD can be classified based on estimated GFR values. A GFR of 90 plus indicated normal kidney function. Between 89-60 mildly reduced kidney function, between 28-40 could indicate moderately reduced kidney function. It is normal for creatinine measurements and GFR to change from one measurement to other. It may cause changes in stages of CKD and as long as your clinical symptoms are not worsening you need not worry. Do see a doctor for more queries.
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