Devices · Syringes & needles · continued

Follow-up: Dead volume across syringe and needle combinations posts 91–99

Devices › Syringes & needles syringe units worked example subcutaneous injection dead volume Solved

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.

z.okonkwoTL230 Dec 2024#91

t.ibarra, post #51: Taking post #48 at face value and following it one step further. Fixed-needle insulin syringes have the least dead volume of any common configuration. At small doses that difference is a measurable fraction of what you meant to deliver. It is worth checking rather than assuming, which costs nothing. Go to post

Dead volume: residual liquid in the hub and needle after withdrawal. Typical residual is 0.01 to 0.02 mL for an insulin syringe with a fixed needle. Accounting for it matters if precision matters.

16 likes in reply to #51 19mo

system_suitabilityTL3Analytical chemist1 Jan 2025#92

I read post #90 twice before replying, because I had assumed the opposite.

Syringe barrel size: common sizes are 0.3 mL, 0.5 mL, and 1.0 mL. Smaller barrels are more legible for small doses. Larger barrels hold larger volumes. Choose based on your dose.

31 likes 19mo

n.okwuosaTL23 Jan 2025#93

Taking post #92 at face value and following it one step further.

Insulin syringe graduations: U-100 syringes are marked in units where 100 units = 1 mL. Always confirm your syringe is U-100. Confusion between insulin units and milligrams is the most common syringe error.

That is a description of practice, not a recommendation of it.

0 likes 19mo

p.iyer_pharmdTL3Pharmacist5 Jan 2025#94

Following this. I have the same question and no better information than the first post.

3 likes 19mo

e.steinerTL26 Jan 2025#95

a.zamora, post #44: Reporting rather than recommending, on Dead volume across syringe. What happened is above. Whether it should have is a different question and not one I am qualified to answer. Go to post

Barrel size determines resolution and nothing else. A 0.3 mL barrel and a 1 mL barrel deliver the same volume equally well; the smaller one lets you see what you are delivering.

The strength of my opinion here exceeds the strength of my evidence.

23 likes in reply to #44 19mo

tracked_parcelTL2Regular8 Jan 2025#96

Fixed versus detachable needles: insulin syringes usually have fixed needles (no dead volume loss to the hub). Luer-lock syringes use detachable needles (more dead volume). Fixed needles are preferred for small doses.

0 likes 19mo

n.ibarraTL210 Jan 2025#97

This follows post #96 rather than contradicting it.

Sharps containers are a legal requirement for disposal in several jurisdictions and a sensible precaution everywhere. A rigid sealed container is the minimum.

1 like 19mo

k.otieno_statsTL3Statistician11 Jan 2025 · edited#98

s.grahame, post #23: Since Dead volume across syringe keeps coming up, it should probably be a maintained page rather than a recurring thread. I am happy to draft it if someone with more direct experience will review it. Go to post

Worth separating two things that post #95 runs together.

Checked the Dead volume across syringe claim against the primary source this morning. It survives, with a narrower scope than the version quoted here. Posting the narrower scope.

6 likes in reply to #23 18mo

s.rasmussenTL213 Jan 2025#99

The arithmetic in post #96 is right; the assumption feeding it is the part to check.

Genuine question rather than a rhetorical one: has anyone here actually observed Dead volume across syringe, as opposed to read about it? The thread is long and I cannot tell.

7 likes 18mo

This topic was referenced in

0.3 mL versus 0.5 mL versus 1 mL barrels: resolution mattersDevices › Syringes & needles · 114 replies
Reading U-100 graduations, with a conversion table — one year onDevices › Syringes & needles · 7 replies
Second pass at: Gauge and length selection for subcutaneous injectionDevices › Syringes & needles · 58 replies

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