Ratio expressions

   MT Reference Style Guide  >  Medical Transcription Grammar, Usage and Style  >  Numbers  >  Basic rules for percents, proportions, ratios and ranges  >  Ratio expressions

A ratio is a fractional expressoin of relationship between one quantity and another, the value of which is determined by dividing the numerator by the denominator.

Use a colon in place of the word to to express a ratio. Do not use a virgule, dash, hyphen or other mark.

The chemical mixture ratio was 4:3.
Cold agglutinins 1:4.
The ACTH:TSH ratio was elevated on admission.

Use to or a hyphen instead of a colon when the ratio expression uses words or letters instead of numeric values. Use a colon only when expressing the values associated with the ratio.

The myeloid-to-erythroid ratio was examined.
BUT
The myeloid-to-erythroid ratio was 5:1.

I-to-E ratio
FEV-FVC ratio