How to Calculate Mixed Insulin (70/30)

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My professor had this math question on one of our nursing exams and the whole class was stumped.

I don't remember the question word for word but I'll do my best.

You need to give 12units of a 70/30 mixed solution how many units do you draw of each. Regular Insulin __________ NPH ________

My answer was: Regular: 8.4 units and NPH: 3.6 and I got the question wrong. I think I might have just put the answers in the wrong order because you don't want to give more of the fast acting insulin, right? Or am I totally wrong, I'f so can someone please explain, which goes first and why and how to do the math if my math was indeed wrong.

We have another exam Monday and we need to make sure we are doing this right.

Thanks so much! :nurse:

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Specializes in Telemetry.
My professor had this math question on one of our nursing exams and the whole class was stumped.

I don't remember the question word for word but I'll do my best.

You need to give 12units of a 70/30 mixed solution how many units do you draw of each. Regular Insulin __________ NPH ________

My answer was: Regular: 8.4 units and NPH: 3.6 and I got the question wrong. I think I might have just put the answers in the wrong order because you don't want to give more of the fast acting insulin, right? Or am I totally wrong, I'f so can someone please explain, which goes first and why and how to do the math if my math was indeed wrong.

We have another exam Monday and we need to make sure we are doing this right.

Thanks so much! :nurse:

If I'm thinking correctly, you have to use whole numbers for insulin units, and you have to draw up NPH first... so it would be 4 units of NPH, and 8 units of regular.

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Specializes in Telemetry.
If I'm thinking correctly, you have to use whole numbers for insulin units, and you have to draw up NPH first... so it would be 4 units of NPH, and 8 units of regular.

It won't let me edit, and I had it backwards- you draw up regular first.

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Specializes in Med-Surg, Wound Care.
My professor had this math question on one of our nursing exams and the whole class was stumped.

I don't remember the question word for word but I'll do my best.

You need to give 12units of a 70/30 mixed solution how many units do you draw of each. Regular Insulin __________ NPH ________

My answer was: Regular: 8.4 units and NPH: 3.6 and I got the question wrong. I think I might have just put the answers in the wrong order because you don't want to give more of the fast acting insulin, right? Or am I totally wrong, I'f so can someone please explain, which goes first and why and how to do the math if my math was indeed wrong.

We have another exam Monday and we need to make sure we are doing this right.

Thanks so much! :nurse:

That's a bizarre question! If you needed a 70/30 ratio insulin, you use a commercially prepared solution. If you have to give NPH and Regular the order has to be specifically ordered for each number of units for each type insulin. No doctor is going to write an order like that, and if they did I wouldn't be giving it until clarified.

Gotta love nursing school....testing on the real world...not so much!! LOL!

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try the web site drugs.com that may be able to help or ask a pharmacist they are more than willing to help if they are nice good luck to you.

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Yeah I thought the question was a bit crazy too. My professor is a bit nutso! We thought the same thing, they have commercially prepared solution to avoid a medication error but of course nursing school wants to prepare you to work in the stone ages so they make us do this crap along with CarePlans that aren't really even used anymore because we are on computers. But what can you do.

Thanks for the help.

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Better yet is that you are not seeing much of the 70/30 mixture anymore as well. There are much newer preparations out there now.

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Specializes in Telemetry.
Yeah I thought the question was a bit crazy too. My professor is a bit nutso! We thought the same thing, they have commercially prepared solution to avoid a medication error but of course nursing school wants to prepare you to work in the stone ages so they make us do this crap along with CarePlans that aren't really even used anymore because we are on computers. But what can you do.

Thanks for the help.

It is my understanding that careplans are still used in most cases. As much as I hate writing them, I have to admit they are a very good tool to learn how to take care of people.

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Specializes in critical care; community health; psych.

The answer is I'd call the pharmacist.

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Specializes in Community Health, Med-Surg, Home Health.

We still use 70/30. I am a fool, but I would think that if the doctor asked for 12 units of 70/30, that is just what I would have pulled up. Altering it in another way would change the concentration of the insulin he is asking that you draw. That is just me...but beachbum's answer sounded good, too. Did your professor answer you guys, yet? When he/she does, please post it.

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Specializes in Telemetry.

Ok, I think I have the right answer for you now, I was just re-reading the post and thought of something else. Already prepared mixtures of 70/30 are 70% NPH and 30% regular.

So my final answer is this: Units can't be divided... so you must round. If the question is asking for 70/30 it would be 70% NPH, so for 12 total units you'd draw up 8 units of NPH, and 30% regular would be 4 units. pull up 12 units of air, put 8 units of air into the NPH. Withdraw your syringe and needle, put the remaining 4 units of air into the regular, then draw up your 4 units of regular. Next draw up your 8 units of NPH.

So its 8 units NPH, 4 units regular.

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When you use 70/30, 70% of what you are giving is intermediate-acting insulin, and 30% rapid-acting insulin.

For example, humulin 70/30 is 70% NPH and 30% regular.

So, if you give 12 units of 70/30, you're administering 8.4 units of intermediate, and 3.6 units of regular.

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