Urine K Creatinine Ratio Calculator

Calculator Inputs

Sample ID or patient code

Sample type

Collection date

Urine potassium

Potassium unit

Urine creatinine

Creatinine unit

Urine volume, optional L

Collection hours, optional

Body weight, optional kg

Custom lower range, mmol/g

Custom upper range, mmol/g

Notes

Formula Used

The calculator first converts urine potassium to mmol/L. Potassium in mEq/L is equal to mmol/L. Potassium in mg/dL is converted to mg/L, then divided by 39.0983.

Creatinine is converted to g/L and mmol/L. Creatinine conversion uses molecular weight 113.12 g/mol. For mg/dL, creatinine g/L equals mg/dL multiplied by 0.01.

K/Cr mmol/g = urine potassium mmol/L ÷ urine creatinine g/L.

K/Cr mmol/mmol = urine potassium mmol/L ÷ urine creatinine mmol/L.

Estimated K mmol/day = potassium mmol/L × urine volume L × 24 ÷ collection hours.

How to Use This Calculator

Enter urine potassium from the laboratory report.
Select the matching potassium unit.
Enter urine creatinine from the same urine sample.
Select the matching creatinine unit.
Add urine volume and collection hours for timed estimates.
Add custom limits if your lab or clinician gives a range.
Press the calculate button.
Download CSV or PDF for record keeping.

Example Data Table

Example	Urine K	Urine creatinine	Volume	Hours	Main ratio	Timed estimate
Spot sample A	45 mmol/L	120 mg/dL	Not used	Not used	37.5 mmol/g	N/A
Spot sample B	22 mmol/L	80 mg/dL	Not used	Not used	27.5 mmol/g	N/A
Timed sample C	60 mmol/L	150 mg/dL	1.8 L	24	40 mmol/g	108 mmol/day

Understanding the Urine Potassium Creatinine Ratio

A urine potassium creatinine ratio compares urine potassium with urine creatinine. The value helps reduce the effect of urine dilution. A very watery sample can look falsely low. A concentrated sample can look falsely high. Normalizing to creatinine gives a cleaner spot sample view.

This calculator supports common laboratory units. It converts potassium to mmol per liter. It also converts creatinine to grams per liter and mmol per liter. Then it reports several ratios. The main output is mmol potassium per gram creatinine. It also shows mmol per mmol creatinine and milligrams per gram.

Why the Ratio Matters

Clinicians may review this ratio when checking potassium loss patterns. It can support a wider review of diet, medicines, hydration, kidney handling, and acid base status. The number should not be used alone. Symptoms, blood tests, urine sodium, urine chloride, and timing can change meaning.

A random urine sample is easy to collect. It is useful when a full day collection is not available. A timed collection adds more detail. If volume and hours are entered, this tool estimates daily potassium excretion. It also estimates creatinine excretion. These estimates depend on complete collection.

Using Results Safely

Laboratory methods vary. Patient context also matters. The calculator lets you enter a custom reference range. This avoids forcing one fixed cutoff for every patient. When limits are provided, the report labels the ratio as below range, within range, or above range.

Use clean values from the same urine sample. Do not mix potassium from one test with creatinine from another. Check the unit printed on the lab report before entering data. Small unit mistakes can create large errors.

Practical Notes

Potassium measured in mEq per liter equals mmol per liter for potassium. Creatinine uses a molecular weight conversion. The tool displays rounded values for readability. Keep the unrounded laboratory report for clinical records.

This calculator is for education and organization. It does not diagnose disease. Discuss abnormal results with a qualified clinician, especially when weakness, palpitations, vomiting, diarrhea, kidney disease, or medication changes are present.

For best records, export the report immediately after calculation. Store it beside the original laboratory document with collection notes attached and review dates recorded.

FAQs

1. What does urine K mean?

Urine K means urine potassium. It measures how much potassium is present in a urine sample. The value is often reviewed with kidney function, blood potassium, medicines, and hydration status.

2. Why compare potassium with creatinine?

Creatinine normalization helps adjust for urine concentration. A spot sample may be diluted or concentrated. Dividing potassium by creatinine gives a more comparable result across samples.

3. Can this replace a 24 hour urine test?

No. A spot ratio can support review, but it does not fully replace a complete timed collection. Use the test type requested by the clinician.

4. Is mEq/L the same as mmol/L for potassium?

Yes, for potassium, mEq/L equals mmol/L because potassium has a single positive charge. The calculator treats these two units as equal.

5. What creatinine unit should I choose?

Choose the exact unit shown on the lab report. Common units include mg/dL, mg/L, g/L, µmol/L, and mmol/L. Unit mismatch can cause wrong results.

6. Why are custom ranges included?

Reference ranges vary by lab, method, age, diet, and clinical purpose. Custom limits let you compare the result with the range given by your own report or clinician.

7. What does the timed estimate need?

It needs urine potassium, urine volume, and collection hours. The calculator scales the collected amount to a daily estimate. Incomplete collections can make this estimate unreliable.

8. Can this calculator diagnose potassium loss?

No. It only organizes and converts numbers. Diagnosis needs clinical review, symptoms, blood tests, urine electrolytes, medicine history, and kidney assessment.