Damn I like almost want to now
I'll take one to the lab with me tomorrow and do some water weights at each level.
You also need multiple syringes from both the same and different batches to truly determine the accuracy across of Motrin syringes. Otherwise you are just determining the accuracy of your syringe.
This guy measures!
Please also provide a cert demonstrating NIST traceability of the scale
Remembering my lab days here...
Let's see here, performing ten sets of tests of ten syringes, each set using a different identical scale, might get you enough results to perform a chi-squared analysis suggesting whether the results are consistent enough to prove your hypothesis.
Please report back!
Very eager to see the results.
Remindme! 24 hours
Top of the line or bottom of the line?
I’m coming back for this
Doesn't that only work at sea level with 4°C?
Seriously.....if you are willing to send it to me.......
I am a science dad.....with access to a 5 place analytical balance and ultra purified water (known density)
I can math this sucker out for you and provide a damn certificate if you want.
You should coordinate with /u/parusmajor69. I don't have access to anything with high precision and I don't think my wife would be pumped about me buying expensive stuff we'll never use again
Alright, but because of lot to lot variance, I'm going to need you to confirm the specific gravity of this lot and use only that the initial accuracy measurements.
Whats the calibration date of that syringe? Or is this for reference only?
It better have a freaking “For Reference Only” sticker on it if so. Otherwise cal it and I want to see their ISO 9001 cert.
Forget 9001. For calibration you need ISO 17025
It's actually the SI prototype for the L believe it or not.
This guy passes regulatory audits with ease.
Bro that syringe is direct impact and therefore a Critical instrument. Process tolerance of +/-0.25 mL, Calibration tolerance of +/- 0.50 mL.
And don't even get me started if that thing fails cal.
I want a validation report for the mass production of this syringe. AQL better show level III sampling plan
5/8 mL gradations, I’ve never seen its equal
It’s the imperial metric system
I have a datasheet from a reputable source that gives hydraulic hose expansion in units of mL/psi per foot.
Is it from a company in England? Because, I swear, those Brits are worse than Americans when it comes to units. I have something from BAE in ftN. That's right - foot•Newtons.
Let me introduce you to one of my favourite flow charts:
As a Brit, I can vouch for the accuracy of this chart. I mean, it's a massive oversimplification but it gives you the gist.
I buy my milk in 1.13 litre bottles because whilst shops are (or at least were) obligated to label it using the metric system, consumers want to buy it by the pint (1.13 L = 2 pints).
Could they have used the cmH2O unit measuring pressure based on the pressure head of water?
It's hose volume expansion in mL in a foot of hose, in response to a psi of pressure change.
That looks like a Motrin syringe.
It's weird how those last forever while the ones walgreens gives out with prescription meds have half the marks smudged off before the end of a 10 day ear infection prescription.
What’s going to vanish first? The marks on a Walgreens syringe or the local Walgreens?
I got savvy to those and started scoring the mark of the proper dosage into the outer wall with a steak knife as soon as so as I got it. Because you’re right, they print those damn things with dry erase markers.
My wife puts a piece of clear tape over the markings. Keeps them on for a long time, and makes it so you can put temporary marks for those ear infections, then replace the tape.
nice!
I think I see a bubble in there. Start over. Aspirate a few times and then draw the meniscus to the line :)
My sister’s name is meniscus.
Ive torn my meniscus a number of times.
Hey, that's his sister you are talking about!
She’s nice lady
So say we all
thanks, always appreciate kindness!
OUR Meniscus!
Woah look at this guy! "Mr. I Still Have A Meniscus" over here!
Well yeah. One…
M’niscus tips fedora
That’s tearable!
We’ll, he better draw her to the line then
Meniscus? I barely know her!
User deleted comment
4d
And your mom goes to college
Dammit my wife makes fun of me because I used to do that and it always just leaked everywhere. I'm ashamed of my poor technique.
Now hold on this is an opaque fluid so op is going to need to do a correction factor with distilled water at 20c. If the water (and medicine) are not at 20c then additional correction factors are needed.
Get it together /u/Vivid-Shelter-146 and /u/Chu_BOT this isn't plastic syringe medicine only reliable enough to sooth a human child, have some accuracy!
Ha. Would hate for that air bubble to land in a kid’s mouth.
Wow they're really gonna say 1.875 and not 1.250?
The bigger crime here is the inconsistency
They aren’t really trying to claim a level of precision so much as state the exact target amount the line is intended to mark (1 and 7/8ths mL). Surely a fair bit of imprecision here in practice, especially when you factor in things like bubbles / that amount of sticky medicine that remains stuck in the tip / the amount that your kid is going to spit out down their shirt / etc.
Honestly, though it would align more with a “sig figs” approach, it would hurt my brain more if the lines were intended to mark units of equal volume but were labeled with numbers of apparently unequal separation, such as: - 0.625 - 1.25 (+0.625 from previous) - 1.88 (+0.63 from previous?!)
[with 3 sig figs]
or: - 0.63 - 1.3 (+0.67 from previous) - 1.9 (+0.6 from previous?!)
[with 2 sig figs]
I'd just go with pictures of progressively more unhappy toddlers
I don't understand the previous comment, all the words and numbers are intimidating. I like your idea better.
Dosage is by weight, so more portly built toddlers
I’d much rather those 3 lines because each line is the recommended dose for a category than have to eyeball between two tiny lines for the sake of having all of the measures
I'd rather the big lines so I don't argue with my wife about how 0.1 ml doesn't matter and we're not over thinking dosages and spending 10 minutes getting it right just for the baby to spit it out anyway.
I felt this comment in my soul
Seems like we're all the same at the end of the day lol
Then you either have to measure the exact amount the kiddo spit out so you can re-dose or you wait the indicated 4-6 hours with a under-medicated upset kid so you can give a full dose and have them spit it out again.
They save $690,000/yr on ink by omitting that zero alone
https://xkcd.com/2319/
trying to avoid rounding up :P
This syringe maker has no clue whether they prefer imperial or metric system.
Maybe I'm missing something, but they're all in mL, where do they use any imperial units?
Metric tends to use 1/10s but imperial is more flexible and kind of built on simple fractions (e.g., 1/8 of a pint is 2 oz, 12 inches in a foot are easily divisible by 2,3,4, and 6 where 10 in metric is really only easily divisible by 2 and 5). This syringe is based on 1/8s where weight and volume in imperial are based on 16 oz in a pound and pint
Here though I believe the markings are like that specifically because those are the different recommended doses based on different baby weight brackets.
That begs the question of why not make the concentration such that the doses are 0.5, 1.0 and 1.5 ml?
I'm speculating that they've kept the concentration the same as it historically was before the us even entertained the metric system and the doses the same (here, 1/8 tsp increments) and just rounded to nearish whole fraction mls.
Metric system was approved by the US government for use in 1866.
SI was adopted in 1960.
Ibuprofen was invented in 1961, and entered the markets around 1969.
There's a ton of things that go into figuring out proper concentrations for meds, and sometimes they work out nicely. And other times... not so much.
Formulation is tricky - you might have problems by increasing or decreasing the concentration in terms of effective dose / available dose. Any change to the formulation requires an expensive process to either 1) perform a new round of toxiclogy and clinical testing to verify the efficacy and safety of the new formulation OR 2) do a less expensive but still pretty expensive and time consuming series of smaller scale tests combined with historical data to submit for appropval for the new formulation.
So, if it isn't broken (or too broken) don't fix it, because fixing it is expensive.
0.875 is a fraction you tend to see on gauges of imperial measurements. mL is metric (obviously).
Ah I see.
I guess my former life in college/grad school studying physics ignored gauges and just understood the actual unit of measure being the focus.
This has nothing to do with imperial, the markings here just mark the common dosages depending on age.
this probably has nothing to do with the syringe and everything to do with the dose size of the medicine it came with.
Motrin FTW
What the allowable percent error?
It's my precious baby so zero. I need that 0.005ml accuracy!
Let me translate to Freedom Fractions, 1.875 mL is:
- 1/8th Tablespoon
- 3/8th Teaspoon
I need it in bald eagles per football field
Three feathers per down. Gotta cross multiply by one Moon Landing.
Manned or unmanned?
Thank you haha finally someone else that understands sigfigs.
I mean it's really 1 and 7/8 but when converted to decimal it doesn't make sense for that precision.
There are 2.0000 kinds of people in the world, those who understand sig figs and those who don’t.
I’ll be using this. Thank you!
There are also 10 kinds of people in the world... those who understand binary, and those who don't
There are 3 kinds of people in this world, those who can count and those who can't
there are 2 kinds of people in this world, those that can infer with incomplete information.
I see what you did there!
It’s in mL and goes by eights?
The best(?) of both worlds!
It's not a good application of sig figs. It's accurate to the nearest 5/8th of a mL not the nearest thousandth of a mL. But no one wants to see fractions with metric units.
It's not a good application of sig figs.
Agreed. However:
…not the nearest thousandth of a mL.
Worth noting: a particular level of “sig fig” precision isn’t specifically aligned with a particular decimal place of the unit — e.g.: - 0.001 mL has 1 sig fig - 0.012 mL has 2 sig figs - 1.250 mL has 4 sig figs
[and all of the above show precision to the thousandth of a mL] - 0.1 mL has 1 sig fig (like the first number above, but this time only reflecting precision to the tenth of a mL, not the thousandth as before) - 0.100 mL has 3 sig figs (but still only reflects the same “thousandth of a mL” precision as that very first, single-sig-fig example above)
A number of sig figs is only tied to precision to a particular decimal place when a number is shown in scientific notation (e.g. in proper scientific notation, 4 sig figs would always be #.### x 10[exponent] with the initial # being a non-zero digit - i.e. showing a thousandths place - but since there’s a possibly-variable exponent, this becomes divorced from any particular decimal place of the actual real world unit, such as “thousandths of a mL”).
Found the nerd. Thanks for the analysis. I loved it!
This syringe follows standard KSP rocket sizes.
I don't know how to strap any boosters to this syringe but I'm certain the answer is more struts
It only has the markings for the specific drug it came with…I think.
I grabbed a bunch of syringe from work that have proper mL increments.
thats weird numbering to me. it's like they wanted to convert mph to kph.
Shit posting about $0.02 syringe -> reading FDA guidelines and learning something for real.
Thanks for sharing. Actually pretty interesting to read.
Line thickness has got to cover .005 ml at least lol
Easily lol. Underappreciated comment
Being able to pull to exactly 1.875 with your eyes closed is part of the dad Olympics.
As a chemist (industrial) and former university science tutor this is hurting me….
The box recommendations tends to underdose for safety
Usual dose for ibuprofen (Motrin) is 10 mg / kg. This works out to 100 mg / 10 kg (22 pounds). Usual concentration is 100 mg / 5 mL, so a 10 kg kid gets 5 mL. (Note that infants Motrin is a different concentration!)
Acetaminophen (Tylenol) is 15 mg / kg, with a concentration of 160 mg / 5 mL, so roughly a 10 kg kid gets 5 mL.
Can alternate 6 hrs for ibuprofen, 4 hrs for acetaminophen, so can stagger them to keep the fever down.
When hydrating, slow slips frequently (a sip every minute) works wonders in hydration and can prevent an IV/ER visit.
Just some peds ED hacks for y'all.
Do you work in a pediatric Ed? I figured there were huge safety margins on infant Tylenol and ibuprofen but I'm still concerned about how often we're giving it to him. It seems better to deal with fever and pain so he stays hydrated and sleeps but I just don't know if we're giving too much
Pharmacist here- each drug 4 times a day is totally safe to do. See a doctor if a week goes by, but with their advice/monitoring you could still keep going!
This is what happens when somebody with strong imperial background tries to do metric.
Is it measured from the top or bottom of the meniscus?
There is no was that is accurate
I'd maybe give 1.9 +/- 0.1 ml but even that feels generous.
Baby is spitting half of it out anyway so like who cares about 0.005 ml?
You mean you don’t weigh the baby before and after to find the total amount consumed and administer more medicine until the correct dose has been given?
The dynamic range on that scale would be impressive
It’s not my area of expertise but maybe weigh them in a vacuum?
User deleted comment
4d
There's no meniscus in a full syringe, unless you count the convex profile of the plunger
This syringe is gonna give me nightmares.
As much as I hate it, and agree with you about the insane sig figs, it’s actually stating to make sense to me.
Tylenol (in the US) is 32 mg/ml. So each line here is 20 mg. And it’s just easier to multiply 32 mg/ml by a decimal than it is by a fraction.
Lol yeah I mean it's super pragmatic to not confuse panicking parents with no laboratory skills. You just have baby weight ranges and one of 3 lines.
I'm sure the numbers are just so the dose fits an mg amount and is just a historical artifact that they ended up as 1/8 ml intervals.
Everything becomes much simpler when you start measuring the volume of your medications in pounds
https://www.reddit.com/r/mildlyinteresting/comments/lsozvd/my_dogs_meds_came_with_syringes_that_are_measured/
This is actually brilliant but new parents are too uptight
The stamped graduations on mass produced syringes probably aren’t accurate to 2 sig figs.
That’s it… time to bust out your favorite Gilson and get reeeeaaaaallll accurate!
.628 mL is roughly 1/8 tsp, which means this is probably for something like infant tylenol?
Make sure eye level w the meniscus otherwise it’s off .0025!
I wonder if the measurements account for the 20% extra that sticks to the outside.
I exclusively use this syringe to draw 2 mL. Sue me.
I bet I can pull 2 ml with this syringe more accurately than you. Fite me
No deal, I don't kid myself that I could beat a bot at precision measurement
This is what you get when you mix up Imperial units with normal units.
This post just reminded me that I was in a band called "Sig Figs" over the summer when I was 13. Good times!
I have at least ten of those same exact syringes in my house.
It’s actually bothering me that they have a different number of sig figs for the first two lines. 1.88 mL would make me a little happier.
Think of the shareholder savings too
No need for sig figs here, the correct dose of Motrin and Tylenol is whatever the kids doesn’t spit out.
I mean I usually do whatever he doesn't spit out from 2 doses. The body has ways of shutting it down
Accurate to one millionth of a liter; amazing.
Dude yes, thank you. I’m a PhD chemist, worked in pharma my whole life. When I first saw these things I immediately thought.. they cannot possibly report that level of accuracy!
That's weird numbering. Shouldn't it be .1.2.3 ml and so on?
Your measuring tape doesn't go 5/8, 5/4, 17/8?
I'm irrationally angry your numbers aren't at a constant interval
He just messed up the math on the last one. Should be 15/8. The interval is 5/8. 10/8 (5/4) and 15/8 (doesn't simplify).
Dang it. What is 8+7
I have it on good authority that it's 17
Nopes. I am in Australia if that makes any difference
So just reversed?
8/5, 4/5, 8/15 then.
Those are the possible doses depending on weight. That's why. Otherwise it would be strange
Did they just convert some imperial unit to millilitres?
1.25 ml is about ¼ teaspoon.
Assuming the concentration of the ibuprofen solution is 40 mg/mL, each 0.625 mL step works out to being 25 mg worth of ibuprofen.
There's a lot of things that go into creating and determining a proper solution for a medicine, and sometimes they work out. And other times, they don't, and you end up with odd looking amounts.
https://www.panadol.com/en-au/childrens-dosage-charts/
Our doages are also like .6 .9 1.2 etc. we don't have 2 or 3 digits after decimal
The dosage is in 5/8ths of a mL depending on age. So consider it the one two and 3 dose mark, but they gave you the actual volume.
Thank you! The best I can think of is a liability issue. They got approved for a fraction of a dose, and need to be as close as possible to that.
Need a pediatric titraton set up to ensure its accurate.
I know these decimals by heart only because I cut paper for a living, never seen this on a syringe before
I'm really surprised no one commented on the dog
more than the sig figs it's the increments of 0.625 that's causing an eye twitch. why?
Because they’re tbsp conversions.
Is that the uptake or W.D.?
IIRC you’re supposed to round one past the given number, so we are in fact looking at 5 sig figs on this bad boy.
You’re a smidge off, just sayin
I don't believe you. I'm pretty sure the orange touches black
I see space. Look at the left side. .009 due to nonright angle. Send it back. Defective
Skill issue. I bet I'm 1.875 +/- 0.001. *as long as I can trust the calibration of the syringe.
** Baby spit it all out and laughed so we'll never know
Stupid babies ruin all the fun
We just need a standard baby and then we can get to the more important business of slinging ibuprofen and seeing who's better
Touché. May the odds be ever in your favor.
Darn it! I really needed one but I was hoping for .6256
Almost! Just not quite precise enough.
No worries, you can trust it to be accurate because a split second before the plunger was applied to the medicine bottle, it had been calibrated by top members of the state and federal Department of Weights and Measures to be dead on balls accurate.
I have come to point where I just poor some in a cup to get the amount I need and poor it back in.
2 sig figs is pushing it for this sort of thing.
Precision: Good
Accuracy: Bad
What's this?
Used these all the time when I worked Peds ICU. Those fresh babies had some seriously precise dosages ordered.
You didn't have more accurate tools in the ICU?
The real crime here is paying 5x for the infant version versus the children's that is just a less concentrated solution...
I have heard this many times but when I bought this it was the same price per mg of ibuprofen for both and the infants is more concentrated which is better. Believe me I am super stingy about stupid name brands and weird packaging
I was a math major. I’ll leave it as an exercise for the chemistry majors to think about such real life example. 😂
Chem major here. I highly doubt that is accurate out to that many decimal places. Use a calibrated micropipette instead. 😂
Not trying to judge but you went past the line
I know what I'm about.
It's actually using octal. It's only 2 sig figs if you convert (1.875 base 10 is 1.7 base 8)
Yeah we did. Syringes accurate to the tenth of a mL
Your QA manual should address this. Be sure to compare to the NIST traceable cert and perform calibration checks.
I mean I get it and it matters like less than zero. My wife doesn't consider a different between 0.625 and 1.25 ml. It's just odd to me and I was joking in the original post but now I've become really curious about the timeline of how these concentrations and doses were picked
Serious Precision!
I have my first kid about 1.872ml one time and no worky. Let the teething continue
You monster that poor baby
2 missing replies
I'm going to need you to determine the accuracy of this syringe and report back.