Use P/F Ratio when you need to compute the PaO2/FiO2 ratio used to grade oxygenation impairment; the inspired fraction must lie strictly between 0 and 1. Enter Arterial O2 and Inspired oxygen fraction using the definitions and units below so the result can be reproduced.

Arterial O2

A finite measured or assumed value, expressed in mmHg.

Inspired oxygen fraction

A finite measured or assumed value from 0 through 1.

The published tool contract uses this rule: Compute the PaO2/FiO2 ratio used to grade oxygenation impairment; the inspired fraction must lie strictly between 0 and 1.

P/F ratio

The calculated p/f ratio.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small. Inspired oxygen fraction must remain between 0 and 1.

Retain the original Arterial O2 and Inspired oxygen fraction values and their units alongside the result. 260/230 Ratio is useful when you instead need to calculate the A260/A230 purity ratio used to detect organic compounds and salts carried over from extraction. 260/280 Ratio provides another view by helping you calculate the A260/A280 purity ratio used to assess nucleic acid contamination by protein.

• 260/230 Ratio

  Calculate the A260/A230 purity ratio used to detect organic compounds and salts carried over from extraction.

• 260/280 Ratio

  Calculate the A260/A280 purity ratio used to assess nucleic acid contamination by protein.

• APTT Ratio

  Compute the activated partial thromboplastin time ratio as the patient APTT divided by the control APTT.