Intake and Output (I&O)

Intake and Output (I&O)

I&O records measured fluid entering and leaving the body over a defined interval. The care team interprets the totals alongside weight, clinical condition and laboratory data.

CNAs measure assigned oral intake and output using the correct marked container and record actual consumption promptly. Use mL, identify the interval and report missed or spilled collections rather than inventing a volume. IV administration and clinical interpretation are not routine CNA duties.

Useful Conventions

• A U.S. fluid ounce is approximately 30 mL for routine care calculations: 8 fluid oz is approximately 240 mL.
• Ice chips are commonly counted as half their measured volume; follow facility policy or measure melted volume.
• For a weighed brief, subtract the dry brief weight. A 1 g increase approximates 1 mL of urine only when other material has not contaminated the measurement.
• Include irrigation input separately so measured drainage is not mistaken for urine production alone.

Do not record sweat or other unmeasured losses as though directly measured. A nurse considers these insensible losses when assessing balance. There is no universal requirement for intake and measured output to match within 200-300 mL.

Follow the resident-specific intake prescription and output-reporting limits. Low output, absent catheter drainage, new swelling or breathing difficulty should be reported promptly.

Use the current care plan and the applicable state rules. Open RN guidance on measuring intake and output.