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June 29, 2000


Question from Fleetwood, Pennsylvania, USA:

My daughter is 18 months old, 30 pounds, and was diagnosed with Type 1 diabetes two weeks ago. I’ve searched your index of previous questions and have determined that U10 dilution is my only hope of obtaining a 0.2-0.5 resolution. Can you suggest dilution technique or website which explains dilution?


From: DTeam Staff

Before you do anything, discuss your plans with your child’s physician. It is very easy to dilute insulin, but also easy to make a mistake. I usually try to pick a dilution that is easy to mix with existing syringes and allows patients to draw up their total dose in a syringe totalling 5-15 “lines” on the syringe. If you use more than 1 insulin, you don’t have to dilute them the same strength.

To make a 1/10th dilution (U 10) Mix 1 part insulin and 9 parts diluent in an empty sterile vial:

i.e., 1 cc insulin (100 full strength “units”) and 9 cc diluent,

or, 0.3 cc insulin (30 “units”) full strength insulin or 30 “lines” on a 3/10 cc syringe) and 2.7 CC diluent (3 CC syringes are available to accurately measure 2.7 CC),

or, 0.1 CC insulin (10 “units” full strength insulin) and 0.9 CC diluent (90 “units” on an insulin syringe) You can either use a 1 CC insulin syringe or a 1 CC TB syringe to draw up the 0.9 CC accurately. If you use the 1 CC insulin syringe, just keep in mind, that each line on the 1 CC syringe represents 2 “units” of full strength insulin, not 1 “unit” of insulin as on the 3/10 and 1/2 CC insulin syringes.

The above can be called either U 10 insulin (10 units/cc), 1/10th strength insulin, or a 1:9 dilution. When you use this diluted insulin, each “line” that you draw up on a 3/10 cc syringe is really 1/10th “unit” of insulin.

Once you are using the diluted insulin, I find it easier to write down how many “lines” of insulin you draw up and just record the dilution, rather than do the math each time and figure out how many “real units” of insulin you are giving. This way, you can just make small changes of 1/2 to 1 “line” at a time of an individual insulin.

The insulin manufacturers provide diluent for each type of insulin and empty sterile mixing vials free of charge. They will only ship the diluent and mixing vials to a physician or pharmacy, so your doctor or pharmacist will have to contact them.

As you can see, there is a lot of room for mistakes, so I suggest you work this out with your child’s own physician.

Additional comments from Dr. Larry Deeb:

Lilly makes a diluting fluid and you can use it to make any strength you choose. I have some patients using U10 and it works, that is the diluting. Please do check with your endocrinologist; this is not conventional treatment and some are uncomfortable with diluting. An 18 month old is always a challenge, even for us gray-haired docs.

Additional comments from Dr. Stuart Brink:

You should be working with your diabetes team for dilution techniques they prefer. We usually suggest a 1:10 dilution using diluent supplied free of charge from either Lilly or Novo Nordisk manufacturers. This also means that each line on the syringe really equals 0.1 unit and so dose decisions are pretty easy to avoid confusion. We make batches for a month and then discard to ensure safety and sterility and have not had any problems with this protocol for more than 20 years.


[Editor’s comment: To help you with measuring small doses, you might want to try the new ReliOn syringes with half-unit markings.