rounding

[ljbutler]

I am confused about the rounding for med math. Would 0.6666666 mL always be rounded to 0.7 or does it depend on if it is mg, mL , etc?

What about 1.6666666?

[Daytonite, BSN, RN]

0.6666666 is a number expressed as a decimal and can be rounded to 0.7

mg and mL are units of measurement, not numbers.

[EricJRN, MSN, RN]

Often it depends on how many decimal places are used in each component of the original question or calculation, a concept known as significant digits.

If I'm on the unit and calculating a volume or dosage, the answer usually depends on my equipment. In giving a small dose of medication, it makes sense to round to two decimals, since this is the most precise that my 1 mL syringe will get (the big dashes are 0.1 and the little ones are 0.01).

[care4u2010]

GENERAL RULES FOR ROUNDING OFF

General Rounding Rule: When rounding off numbers 5 and above, round up.

Numbers below 5, round down

Calculation Caution: Round appropriately when performing calculations that require

multiple steps. Do not leave unrounded numbers in your calculator when you go to the

next step.

I. Capsules and tablets

Whole capsules or tablets (which are not scored) should be rounded to the nearest

whole number. The difference should not exceed 10% of total amount ordered.

Ex.: 1.8 capsules = 2 capsules

1.5 scored tablets = 1 ½ tablets

II. Liquid medications by mouth

If unable to accurately measure dose on available medication cup, use a syringe

to obtain accurate measurement of dose.

III. Milliliters

A. Volumes greater than 1 ml. or cc: Volumes using ml or cc’s greater than 1

should be divided to the hundredths place and rounded to the nearest tenth.

Ex.: 1.25 ml = 1.3 ml

1.24 ml = 1.2 ml

B. Volumes less than 1 ml or cc: Volumes using ml or cc’s less than 1 ml should

be divided to the thousandths place, and rounded to the nearest hundredth.

A TB syringe is appropriate for this measurement.

Ex.: .969 = .97 ml

.963 = .96 ml

IV. Converting pounds to kilograms

When converting pounds to kilograms, the weight should be carried to the

hundredths place and rounded to the tenths place.

Ex. 170 lbs = 77.27 kg = 77.3 kg

160 lbs = 72.72 kg = 72.7 kg

V. Drops

Calculate to the tenths place and round off to the nearest whole number.

Ex. 15.4 = 15 drops

15.5 = 16 drops

VI. Setting an IV pump (Exception: do not round off for heparin infusions)

Round fractions of ml to the whole ml using the general rounding rule.

Ex. 123.3 ml/hour = 123 ml

123.7 ml/hour = 124 ml