HOSA Medical Math Formulas

basic dose calculation formula

dose (mL) = [desired dose (units) ÷ dose on hand (units)] × volume (mL)

IV drop rate formula

flow rate (gtts/min) = [volume (mL) ÷ time (min)] × drop factor (gtts/mL)

IV mL rate formula

flow rate (mL/hr) = volume (mL) ÷ time (hr)

dose calculation by weight

dose (mL) = weight (kg) × dosage (mL/kg)

amount in IV fluid

dosage amount (g) = concentration (%) × volume (mL)

metric body surface area (BSA)

BSA (m²) = √{[height (cm) × weight (kg)] ÷ 3600}

household body surface area (BSA)

BSA (m²) = √{[height (in) × weight (lbs)] ÷ 3131}

normal saline (NS)

NS = 0.9% NaCl

fahrenheit to celcius

°C = (°F - 32°) × (5/9)

celcius to fahrenheit

°F = (9/5) × °C + 32°

Young's rule

child's dose (mL) = {child's age (yr) ÷ [child's age (yr) + 12]} × adult dose (mL)

Fried's rule

infant's dose (mL) = [age (months) ÷ 150] × adult dose (mL)

household Clark's rule

child's dose (mL) = [child's weight (lbs) ÷ 150 lbs] × adult dose (mL)

metric Clark's rule

child's dose (mL) = [child's weight (kg) ÷ 68 kg] × adult dose (mL)

concentration of same solution

amount of solute ÷ amount of 1st solution = amount of solute ÷ amount of 2nd solution

child's dose calculation from BSA

child's dose (mL) = [child's BSA (m²) ÷ 1.7m²] × adult dose (mL)

fluid maintenance requirement 0-10 kg

required daily fluid (mL) = 100mL/kg × infant's weight (kg)

fluid maintenance requirement 10-20 kg

required daily fluid (mL) = 1000mL + 50mL/kg × infant's weight above 10kg (kg)

fluid maintenance requirement 20-70 kg

required daily fluid (mL) = 1500mL + 20mL/kg × infant's weight above 20kg (kg)

fluid maintenance requirement over 70kg

2500mL (adult requirement)

standard deviation

s = √[ ∑(x - mean)² / (n-1) ]

microdrip rate (no IV infusion controller)

60 gtts/mL

dilution equation

M₁V₁ = M₂V₂, with M = initial/final molarity and V = initial/final volumes