Total Dose: A low dead space 25G, 25mm, (1 inch), orange hypodermic needle, originally developed to help reduce the spread of HIV and other blood borne viruses, when coupled with our own-brand 1ml or 2.5ml syringes reduces the dead space enough to below the 35 microlitres required to extract the extra dose of Pfizer-Biontech COVID and AstraZeneca COVID vaccination from the multi-dose vial.

The total dose orange 25G 25mm needles were designed for the Unifix range and total dose compatible syringes. They also fit some other 2ml (and larger) syringes for detachable needles.

Quantity	Price (exc VAT)	VAT	Price (inc VAT)
10	13p each	20%	16p each
100	£8.00	20%	£9.60
10000	4p each	20%	5p each

FREE shipping on all UK orders over £30

This 25G, 25mm, (1 inch) detachable hypodermic needle is also suitable for veterinary use.
Please note: Total Dose needles do NOT fit syringes that have a dead space reducing spike on the plunger.

Product details
Gauge	25G
Needle Length (inch)	1 inch
Needle Length (mm)	25mm
Hub Colour	Orange
Type	Low Dead Space, fit both Luer Slip and Luer Lock syringes
Manufacturer	Exchange Supplies
Brand	Total Dose
Product Code	TO25
Also known as	LDS orange

What is the dead space volume?
We had the dead space in this product independently assessed at the Research Institute for Industry, Southampton University. Conducted by Dr. Xize Niu and his team, who are experts in microfluidics, the assessment used 2 different highly accurate measuring techniques to determine that the Total Dose needle design reduces the dead space available for blood residue following injection from around 91.6 µL (in a 'standard' Luer Slip needle and 2ml syringe combination) to just 26µL.

Furthermore, high speed imaging of a simulated injection sequence has demonstrated that liquid and air become trapped in the needle hub at the top (farthest from the syringe), and that when blood is subsequently drawn into the needle and syringe, contamination of this void is prevented by this existing water and air, reducing the amount of blood contamination in this area to between zero and 20 µL.

Why is dead space important?
A standard detachable needle fixed to a used 2ml syringe has around 90 microlitres of blood remaining in the dead space between the plunger and the tip of the needle. The Total Dose needle reduces the dead space by having a thin plastic tube that fits down into the tip of the syringe, filling this void, and preventing the accumulation of blood.

This significantly reduces:

• the amount of virus that could be left in the used syringe, and
  

• survival time of any virus left in the syringe.
  

The dead space in syringes is a risk factor that has only recently come to light, but we know that the risk of HIV infection is related to the dose of virus that is injected - and the work of Bill Zule, an academic from the USA, has concluded that the reduction in dead space offered by insulin type syringes (such as the Unisharp fixed) and total dose low dead space needles may reduce the volume of blood to less than that which is required to transmit HIV infection.

The same may not be true of hepatitis C for a syringe shared immediately after use, however, we know that HCV survival in syringes is related to the volume of blood and so it is likely that the Total Dose needles have significant potential to reduce hepatitis C transmission as well.

To read the review of the literature, and the latest thinking on the importance of low dead space syringes, read the article by William Zule and colleagues in the International Journal of Drug Policy, by clicking here.

For more on the issues surrounding the use of low dead space syringes and needles to reduce blood borne virus spread, go to the low dead space syringes facebook page (which is run by Bill Zule), and click like to get occasional updates in your timeline.