How well your kidneys filter, and the salts they balance. 11 markers, each with the guideline behind it, the ranges, what can affect it, what Passion Health does if it's out of range and when to retest.
Medically reviewed by Anantha Chentha, MD, Co-Founder and Chief Quality Medical Officer · October 30, 2026. Meet our cliniciansNext review: October 2027
How well your kidneys filter, and the salts they balance.
A muscle waste product filtered by the kidneys.
Why it matters: Used to calculate eGFR.
Ranges: Your lab's range applies; it varies with muscle mass.
What can affect it: Muscle mass, hydration, intense exercise and some medicines.
If it’s out of range: Read through eGFR.
When to retest: Yearly, or more often with kidney risk.
Condition guide: Kidney function test guide
Your estimated kidney filtering rate.
Why it matters: Calculated with the 2021 CKD-EPI equation, which does not use race.
Ranges: Below 60 for more than three months meets the KDIGO definition of chronic kidney disease.
What can affect it: Same as creatinine.
If it’s out of range: A low result is rechecked and paired with a urine albumin test.
When to retest: Within 3 months if low.
Condition guide: Kidney function test guide
Another kidney waste marker.
Why it matters: Part of the metabolic panel.
Ranges: Your lab's range applies.
What can affect it: Hydration, protein intake and bleeding in the gut.
If it’s out of range: Read with creatinine and eGFR.
When to retest: With your metabolic panel.
Condition guide: Kidney function test guide
Protein leaking into urine, an early sign of kidney strain.
Why it matters: ADA and KDIGO recommend urine albumin testing yearly with diabetes or high blood pressure.
Ranges: Reported as a ratio with urine creatinine.
What can affect it: Exercise, fever, infection and high blood sugar.
If it’s out of range: A high ratio is confirmed with a repeat sample.
When to retest: Yearly with diabetes or high blood pressure.
Condition guide: Kidney function test guide
Used to correct urine albumin for how concentrated the urine is.
Why it matters: Paired with urine albumin to calculate the ratio.
Ranges: Not interpreted alone.
What can affect it: Hydration.
If it’s out of range: Part of the ratio.
When to retest: With urine albumin.
Condition guide: Kidney function test guide
The standard urine test for early kidney damage.
Why it matters: KDIGO grades albuminuria by this ratio.
Ranges: 30 mg/g or higher is increased albuminuria (KDIGO).
What can affect it: Exercise, fever, infection and high blood sugar.
If it’s out of range: Can change which blood-pressure or diabetes medicine fits best.
When to retest: Repeat to confirm; then yearly.
Condition guide: Kidney function test guide
The main salt in your blood.
Why it matters: Some blood-pressure medicines can lower it.
Ranges: Your lab's range applies.
What can affect it: Water intake, water pills and some antidepressants.
If it’s out of range: Out-of-range values are checked against your medicines.
When to retest: With your metabolic panel.
Important for heart rhythm and muscles.
Why it matters: ACE inhibitors, ARBs and water pills can shift it.
Ranges: Your lab's range applies.
What can affect it: Medicines, kidney function and how the sample was handled.
If it’s out of range: A high or low value is rechecked promptly.
When to retest: After starting some blood-pressure medicines.
A salt that moves with sodium.
Why it matters: Part of the metabolic panel.
Ranges: Your lab's range applies.
What can affect it: Hydration and acid-base balance.
If it’s out of range: Read with the other electrolytes.
When to retest: With your metabolic panel.
Reflects your blood's acid-base balance.
Why it matters: Part of the metabolic panel.
Ranges: Your lab's range applies.
What can affect it: Kidney and lung conditions, vomiting and some medicines.
If it’s out of range: Read with the other electrolytes.
When to retest: With your metabolic panel.
Important for bones, nerves and muscles.
Why it matters: Part of the metabolic panel; read with albumin.
Ranges: Your lab's range applies.
What can affect it: Albumin level, vitamin D, parathyroid glands and water pills.
If it’s out of range: A high value is rechecked and may prompt a parathyroid test.
When to retest: With your metabolic panel.
Education only. Your clinician interprets results with your history. Reference ranges vary by lab; your report shows ours.