Syringe for obtaining a target volume of blood

A method of filling a syringe with a target volume of blood, the method comprising:

• providing a syringe comprising:
• (a) a barrel comprising a first barrel structure and a second barrel structure;
• and
• (b) a plunger comprising a filter, a first plunger structure, and a second plunger structure,
• wherein:
• (i) the plunger is arranged within the barrel to be displaceable along a displacement direction,
• (ii) the first barrel structure and the first plunger structure are configured to cooperate together to form a first stop and the second barrel structure and the second plunger structure are configured to cooperate together to form a second stop,
• (iii) the first stop is configured for positioning the filter at a predetermined location along the displacement direction thereby defining a target volume of blood and a buffer volume, and
• (iv) the second stop is configured to stop the plunger from expelling more than the buffer volume for obtaining the target volume of blood when pushed towards a distal end of the syringe along the displacement direction,
• (v) guiding blood into the syringe causing air to move from the barrel through the filter of the plunger towards outside of the syringe as long as the filter is not in contact with blood,
• (vi) causing a contact of the blood with the filter thereby changing a permeability of the filter from being gas-permeable when the filter is not in contact with blood to being gas-impermeable when getting into the contact with blood, and
• (vii) fluid tightly sealing the plunger by changing the permeability of the filter into being gas-impermeable.

A syringe for obtaining a target volume of blood, the syringe comprising:

• (a) a barrel, and
• (b) a plunger comprising a channel and a filter, the filter being inside of the channel,
• wherein:
• (i) the plunger is arranged within the barrel to be displaceable along a displacement direction,
• (ii) the barrel defines a first portion and a second portion,
• (iii) the first portion is configured for positioning the filter at a predetermined location along the displacement direction thereby defining a syringe volume having a target volume and a buffer volume,
• (iv) the second portion is configured to stop the plunger from expelling more than the buffer volume when the plunger is pushed towards a distal end of the syringe along the displacement direction,
• (v) the barrel comprises a proximal end at which a first opening for introducing the plunger into the barrel is located,
• (vi) at the distal end of the barrel, a second opening for receiving the target volume of blood is located,
• (vii) the filter is configured to be gas-permeable when the filter is not in contact with blood, and wherein the filter is configured to become gas-impermeable when getting in contact with blood,
• (viii) the plunger is fluid-sealing when the filter is gas-impermeable,
• (ix) the plunger is configured for guiding air out of the barrel and through the channel and filter towards outside the syringe, and
• (x) a distal end of the plunger is configured to translate past the first portion with the first portion being positioned inside of the barrel.