The physician orders testosterone 170 mg 1M weekly for hormone replacement. The medication is supplied in 200 mg/mL. How many milliliters will the nurse administer? Do not provide the unit of measurement. Only provide the number. Round to the nearest hundredth, 2nd decimal place.

To calculate the volume to administer, use the standard dosage-calculation formula: volume to give equals the desired dose divided by the dose on hand, multiplied by the volume on hand. The desired dose is 170 mg, the dose on hand is 200 mg, and the volume on hand is 1 mL. Setting up the equation: 170 mg ÷ 200 mg × 1 mL = 0.85 mL. Rounding to the nearest hundredth confirms the answer is 0.85 mL. A common error students make is inverting the ratio — dividing 200 by 170 — which gives approximately 1.18 mL, an incorrect result. Another potential mistake is misreading the concentration as 200 mg per dose rather than 200 mg per mL, which could lead to the wrong volume being drawn up. Because this is an intramuscular injection of testosterone, an oily suspension, accuracy is important to avoid administering too large a volume into a single site, which can cause pain and poor absorption. The correct volume of 0.85 mL falls within the safe range for an IM injection in a typical adult muscle site.