Diabetes is a חולי שיש בו סכנה, an illness that poses a danger to life1. As such, everything necessary for caring for diabetes must be done on Shabbos, even if it includes איסורי תורה. (see Shulchan Aruch, Orach Chaim 328, Rambam, Hilchot Shabbos 2, שמירת שבת כהלכתה, ch. 32)

However, if it makes no difference to the speed/efficacy in which care is provided, one should minimize the amount of חילול שבת, both in the amount of actions done, as well as in the severity of the prohibitions violated (Biblical vs. rabbinic). [Shmiras Shabbos K'Hilchasa, 32:27-29]
Therefore, blood sugar testing, which is a medical necessity for PWD (especially those with insulin-dependent DM), must be done on Shabbos, but the prohibitions violated should be limited.

How should one check blood sugar on Shabbos, while minimizing Shabbos violations?

1Whether due to hypo or hyperglycemia, both which can are preventable -- given that they are discovered before they happen, like by blood sugar check.


1 Answer 1


Since this is a question, I will answer it with practical advice. Questions about the particular halachos mentioned in passing may be asked separately.

Here's what I've been told to do, with illustrative pictures. Before changing anything about what you do personally, you should talk to both your rabbi and your doctor. What is written here is just practical advice, gleaned from years of experience (and conversations with Rabbi Hirsch Meisels).

Step 0

What are we dealing with?
blood testing set
A: blood sugar meter (measures blood sugar levels)
B1: strip container (contains strips)
B2: testing strips (brings blood into meter)
C: lancet (draws blood)

Step 1

Inserting strip

In order to use the meter, the strip has to be inserted. Doing so turns the meter on, and possibly created a kli (vessel), as neither piece is usable by itself. As such, a shinui should be used to insert the strip into the meter.

Meter with strip in it:

meter and strip

Suggested shinui (insert halfway, and push against a table):

meter and strip shinui

Step 2

Drawing blood ("lancing")

Drawing blood to test is usually done by pressing the button on the lancet with a finger, like this:

regular lancing

To replace this possible איסור דאורייתא (Biblical prohibition) with a שינוי (different way of doing it, considered halachically to be less severe), lancing should be done with a knuckle, like this:

shinui lancing

Anecdotally, I've used about everything, from elbows to forehead. (Yes, forehead :P )

Step 2.5

Squeezing blood

Squeezing blood out of the wound (in case there is not enough from just the lancing) is problematic on Shabbos, due to the prohibition of dash (the weirdest form of squeezing liquid from solid you're ever likely to see), so it should be done with a shinui if possible.

Regular squeeze:

regular squeeze

Suggested shinui: use the lancet

shinui squeeze

Then put the drop of blood on the strip, like normal, and collect the result. Do not turn off the meter after use, because this serves no purpose on Shabbos (unless the battery will die, and this meter is needed for more tests over the course of Shabbos).

  • I wonder if putting the drop of blood on the strip like normal is dyeing, and if so whether letting it drip onto the strip from above would (a) act as a sort of shinui and (b) be ok medically. Commented Nov 28, 2014 at 3:37
  • @MonicaCellio Interesting idea; I'd never thought about that. I don't think it would be a problem of dyeing though, because I'm pretty sure that nothing gets colored -- just a small space in the strip gets filled.
    – MTL
    Commented Nov 28, 2014 at 3:48
  • Oh, the strip is a container rather than being absorbent? I didn't know that. Is it worth mentioning that in your last paragraph, or is that something that would be obvious to anybody for whom this is a practical matter? Commented Nov 28, 2014 at 3:49
  • Your Shinui in Step 2 might not be effective as a Shinui because the needle is still poking in the same way.
    – Double AA
    Commented Nov 28, 2014 at 4:02
  • @MonicaCellio I'm not 100% sure on that count....I'll check it out, but I've pulled apart enough used strips to be reasonably sure that there is a space between the top and bottom halves of the strip, where the blood goes in. On some strips (eg Freestyle) the place where the blood goes is black, so it's hard to tell; but on others (eg OneTouch, Bayer), there is a clear layer of plastic so whatever coloring takes place, it's just blood showing through the clear plastic. Further research is called for.
    – MTL
    Commented Nov 28, 2014 at 4:24

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .