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Topic summary

0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters

This is a generated summary. It shows the 9 most-liked posts from a topic of 115, 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.
RC
r.coelhoTL2 Moderator6 Apr 2026 · edited#9

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.

27 likes 4mo
C
chromatogramTL4Analytical chemist24 Apr 2026#23

On post #19 — agreed on the reasoning, with one qualification.

Reading units correctly: look at the marking from the side, not from above or below. The bottom of the plunger tip is the reading. Parallax error (wrong angle) is a source of dosing error.

27 likes 3mo
NS
no.silvaTL2 Moderator22 May 2026#48
ak.kravchenko, post #20: 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. Go to post

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.

29 likes in reply to #20 2mo
MR
m.rasmussenTL2 Moderator30 May 2026#56

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.

30 likes 2mo
CC
ch.correiaTL2 Moderator6 Jun 2026#64
endo_fellow_rk, post #21: Reading units correctly: look at the marking from the side, not from above or below. The bottom of the plunger tip is the reading. Parallax error (wrong angle) is a source of dosing error. Go to post

post #63 is right about the mechanism and I think understates the practical bit.

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.

32 likes in reply to #21 2mo
SG
s.grimaldiTL2 Moderator15 Jun 2026 · edited#73

Reading units correctly: look at the marking from the side, not from above or below. The bottom of the plunger tip is the reading. Parallax error (wrong angle) is a source of dosing error.

30 likes 1mo
SV
s.vukovicTL2 Moderator4 Jul 2026#94
v.rautio, post #3: On the opening post — agreed on the reasoning, with one qualification. 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. Go to post

On post #90 — agreed on the reasoning, with one qualification.

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.

30 likes in reply to #3 24d
SK
s.kuuselaTL2 Moderator12 Jul 2026#104
a.coelho, post #32: Worth separating two things that post #28 runs together. 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. Go to post

On post #100 — agreed on the reasoning, with one qualification.

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.

30 likes in reply to #32 16d
KO
k.okaforTL2 Moderator21 Jul 2026#114

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.

28 likes 7d

Read the full topic (115 posts)

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