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2.6k

reading mg/mL threads from 2024 and half of it aged badly

Correction Clean Column ×3 Long Haul ×2 Slow Clap ×2

Trying to settle this properly because the thread from last year went in circles.

The claim: insulin syringe matters. The counter-claim: it is measurement error. Both sides have been asserting it confidently for about 16 months without either producing anything.

What would actually settle it is 39 people measuring the same thing the same way. I have started; my numbers are below. They lean one way but not strongly enough for me to declare victory.

If you have data, post the data. If you have an opinion, flair it as an opinion.

3,248 up / 620 down84% upvoted57 commentsid fvk1cc22 Mar 2024

57 comments

30 in this archive, depth 6

best — the order this archive was captured in

u/bac_water_banditMOD327 points·2 years ago

Retitled to remove editorialising. Put the evidence in the body.

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u/andres_sorensen106 points·2 years ago

u-100 syringe, not u-40, or your math is off by factor of 14

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u/marta_weiss30 points·2 years ago

never post a calculation as advice without stating the concentration

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u/georgi_adebayo129 points·2 years ago

The single most useful thing I did was write the concentration on the vial. Stopped all the confusion after that.

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u/rasmus_mensah266 points·2 years ago

stopper coring on the 11th draw because you keep using the same entry point. rotate.

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u/hedda_ekstrom59 points·2 years ago

This is correct. 2mL versus 6mL is the common mistake.

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u/rasmus_mensah16 points·2 years ago

stopper coring on the 5th draw because you keep using the same entry point. rotate.

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u/priya_weiss47 points·2 years ago

show your working or it is unhelpful

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u/zaid_balogun36 points·2 years ago·edited

Yeah, showing the arithmetic is the fastest way for someone to spot the error.

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u/ismael_nwosu59 points·2 years ago

bacteriostatic and sterile water are not interchangeable, do not use them that way

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u/vial_math_verasyringe math207 points·2 years ago

Yeah, showing the arithmetic is the fastest way for someone to spot the error.

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u/piotr_bruun80 points·2 years ago

Cored the stopper on my 5th draw because I kept using the same entry point. Rotate the puncture site.

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u/freya_onwuka39 points·2 years ago

swirl, do not shake, or you are courting oxidation

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u/batch_number_bertievetting11 points·2 years ago

Yeah, showing the arithmetic is the fastest way for someone to spot the error.

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u/alcohol_aversion151 points·2 years ago

i am begging people to write down the concentration

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[removed]100 points·2 years ago

[removed by moderator]

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u/units_not_mgsyringe math30 points·2 years ago·edited

[removed by moderator]

Adding to this: units is doing more work than the comment implies.

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u/nadia_kjaer127 points·2 years ago

Disagree but this is the good kind of wrong — it is specific enough to be checked.

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u/quarter_dose_queenOPlow and slow49 points·2 years ago

Reconstituted at 2mL when I meant 22mL. Caught it because the units looked wrong. Write the concentration.

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u/quarter_dose_queenOPlow and slow121 points·2 years ago

The single most useful thing I did was write the concentration on the vial. Stopped all the confusion after that.

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u/quarter_dose_queenOPlow and slow87 points·2 years ago

5mg vial, 2mL water, concentration is 5/2 — write it on the vial afterwards

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u/cardio_endpoint_c64 points·2 years ago

never post a calculation as advice without stating the concentration

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u/viktor_erdogan42 points·2 years ago

never post a calculation as advice without stating the concentration

Yes, exactly this, and it is the bit that took me 67 weeks to accept.

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u/units_not_mgsyringe math23 points·2 years ago

This is correct. 1mL versus 5mL is the common mistake.

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u/freya_onwuka26 points·2 years ago

never post a calculation as advice without stating the concentration

Yes, exactly this, and it is the bit that took me 66 weeks to accept.

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u/arto_falk70 points·2 years ago·edited

5mg vial, 2mL water, concentration is 5/2 — write it on the vial afterwards

Disagree on that part. 99.0% and 98.9% on the same vial is normal.

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u/saskia_rahimi94 points·2 years ago

No. This is the kind of confident post that gets copied into a screenshot and repeated for years. Where is the evidence.

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u/bac_water_banditreconstitution74 points·2 years ago·edited

Water content matters more than people think. If a vial is carrying residual moisture, your "10mg" is not 10mg of peptide.

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u/cesar_ivaturi40 points·2 years ago

dead space is real and the syringe matters

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u/spain_receta-7 points·2 years ago

Disagree but this is the good kind of wrong — it is specific enough to be checked.

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About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

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