Topic summary

Fixed versus detachable needles: the trade-offs

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

This is a generated summary. It shows the 9 most-liked posts from a topic of 122, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.

h.nwosuTL2 Moderator10 Nov 2024#1

Posting this under the heading it deserves: Fixed versus detachable needles: the trade-offs Everything below is what sits behind that.

I have read the maintained page on this and I still have a gap, so I am asking rather than guessing.

Context: semaglutide, 26 weeks in, currently at a dose I reached by the standard four-week steps. Everything below is my own record rather than anything a clinician told me.

The specific question is the one in the title. What I have already checked: the labelling summary on the relevant documentation page, the two most-linked topics in this subcategory, and my own notes from the last 12 weeks. What I could not find is whether the answer changes at higher doses or whether it is the same arithmetic throughout.

If the answer is "it depends", I would rather know what it depends on than be given a number.

50 likes 21mo

k.fonsecaTL2 Moderator Solution15 Nov 2024#6

On post #2 — agreed on the reasoning, with one qualification.

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.

7 likes 20mo

r.jhannsdttirTL3Regular22 Nov 2024#14

journalclub_wren, post #9: Aspirating before injection: for subcutaneous injection, aspirating (pulling back on the plunger to check for blood) is not necessary and is sometimes discouraged because it is associated with more discomfort. Subcutaneous injection without aspiration is standard practice. Go to post

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.

29 likes in reply to #9 20mo

d.fontaineTL2 Moderator29 Nov 2024#25

Sharps disposal: needles and syringes should be disposed in a sharps container (a rigid, puncture-resistant container). Do not put them in regular trash. Many pharmacies accept filled sharps containers.

29 likes 20mo

s.chowdhuryTL3Regular4 Dec 2024#33

I read post #31 twice before replying, because I had assumed the opposite.

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.

33 likes 20mo

c.ostergaardTL2 Moderator15 Dec 2024#51

31 likes 19mo

h.delgadoTL2 Moderator31 Dec 2024#83

Needle length: typical lengths for subcutaneous injection are 4-6 mm (short), 8 mm (standard), or 10-12 mm (longer). Longer needles are needed for deeper tissue or if you have abdominal adiposity.

31 likes 19mo

r.mcalisterTL3Regular4 Jan 2025#90

y.adebayo, post #36: 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. 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.

30 likes in reply to #36 19mo

WendelboeTL2Member19 Jan 2025#122

Aspirating before injection: for subcutaneous injection, aspirating (pulling back on the plunger to check for blood) is not necessary and is sometimes discouraged because it is associated with more discomfort. Subcutaneous injection without aspiration is standard practice.

31 likes 18mo

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This topic was referenced in

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