TTKG Calculator – Transtubular Potassium Gradient

Written by Great Medico

Updated September 24, 2026 •2 min read

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A kidney or urology number is useful only when you know exactly what went into it. TTKG Calculator – Transtubular Potassium Gradient keeps the inputs and the resulting estimate in one place so the arithmetic stays transparent.

What this calculator does

TTKG Calculator – Transtubular Potassium Gradient uses Serum potassium, Urine potassium, Serum osmolality, and Urine osmolality to calculate transtubular potassium gradient. It follows the exact field flow and engine behavior in this plugin rather than describing a different calculator with the same name. Kidney and urologic calculations often summarize one narrow measurement or historical model. Results should be read with symptoms, laboratory trends, imaging, pathology, and the clinical question that prompted the test.

How to use it

Enter or select Serum potassium, Urine potassium, Serum osmolality, and Urine osmolality. Use the units offered by the calculator and keep paired laboratory or treatment values from the same clinical episode whenever the formula assumes that. If an entry is unknown, do not substitute a guess simply to obtain a number.

How the calculation works

TTKG is calculated as urine potassium × serum osmolality ÷ (serum potassium × urine osmolality). The arithmetic expresses the urine-to-plasma potassium relationship after adjusting for the urine-to-plasma osmolality ratio.

Example

Using the sample values prefilled in this calculator, the primary result is 3.625 (Transtubular potassium gradient). This example demonstrates the plugin’s own calculation path; replace the sample inputs with verified values before interpreting a real result.

How to interpret the result

The number is a renal potassium-handling index under the assumptions of the model. Interpretation depends on whether the clinical situation and urine conditions make the index meaningful.

Limitations and notes

TTKG has physiologic assumptions, including adequate distal sodium delivery and urine osmolality, and its clinical use is limited in many modern workflows. It should not be treated as a stand-alone test of aldosterone action or the cause of hypo/hyperkalemia.