Use this tool to reproduce the documented calculation from laboratory values reported in the required units. It can support verification and education when the applicable patient population and convention are known.

BUN

A finite measured or assumed value greater than or equal to 0, expressed in mg/dL.

Creatinine

A finite measured or assumed value greater than or equal to 5e-324, expressed in mg/dL.

The implementation follows this calculation rule: Compute the blood urea nitrogen to serum creatinine ratio.

BUN creatinine ratio

The calculated bun creatinine ratio.

Calculated laboratory indices are not diagnoses and must not replace clinical interpretation. Assay method, reference interval, age, body size, medications, acute illness, unit conversion, and the population in which an equation was validated can change its meaning. Ratios and percentages become unstable when their denominator is small, uncertain, or defined differently between samples.

Review the original laboratory report, reference interval, trends, and relevant confirmatory tests. When an estimated physiologic quantity matters clinically, use the locally recommended equation or a measured method.

• Anion Gap

  Compute the serum anion gap from sodium, chloride, and bicarbonate.

• Creatinine-Based Clearance

  Compute renal creatinine clearance as urine volume times urine creatinine divided by plasma creatinine and the collection time in minutes.

• Corrected Sodium

  Correct measured serum sodium for hyperglycemia with the 1.6 per 100 mg/dL rule.