Topic summary

Reading a syringe in poor light, and how to avoid needing to — what changed since

Devices › Syringes & needles dead volume subcutaneous injection syringe units needle gauge & length worked example

This is a generated summary. It shows the 5 most-liked posts from a topic of 8, 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.

f.sjobergTL218 Jan 2026#1

Posting this under the heading it deserves: Reading a syringe in poor light, and how to avoid needing to — what changed since Everything below is what sits behind that.

What changes if the standard account of Reading a syringe is wrong? I ask because I have been treating it as settled and I noticed this week that I could not say why.

Working through the consequences rather than the evidence, since others here are better placed on the evidence.

45 likes 6mo

l.dialloTL221 Mar 2026#3

Bookmarking this. I will come back when I have something worth adding.

3 likes 4mo

cannula_driftTL3Regular13 Apr 2026 · edited#4

Post #2 describes the usual case. This is about the unusual one.

U-100 means the barrel is graduated for a solution containing one hundred units of insulin per millilitre. For anything that is not insulin, the units are simply hundredths of a millilitre.

11 likes 3mo

h.amankwahTL24 May 2026#5

cannula_drift, post #4: Post #2 describes the usual case. This is about the unusual one. U-100 means the barrel is graduated for a solution containing one hundred units of insulin per millilitre. For anything that is not insulin, the units are simply hundredths of a millilitre. 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.

Anyone with a larger sample, please post it.

18 likes in reply to #4 3mo

c.delgadoTL21 Jul 2026#8

On post #6 — 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 27d

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