Method and apparatus for measuring precise micro quantities of fluid samples

Claim 1

The disposable apparatus useful for separating a precise volume of liquid sample comprising a precision, self-filling capillary tube weakened at a predetermined point between its ends and adapted to be severed at said point to form a first zone of predetermined known volume and a second zone, holder having a longitudinally extending bore therethrough, said capillary mounted in said bore with portions of said holder extending around said first and second zones; closure means disposed at the open end of said second zone of said capillary and means mounted on said holder for shielding said capillary tube and for severing said capillary tube at said weakened point whereby said first zone remains mounted on said holder and contains a precise known voluMe of said liquid.

Claim 12

A method for separating a precise known volume of liquid contained in a disposable apparatus having a capillary tube mounted in a holder, said capillary tube having a weakened point formed between the ends thereof so as to form a first zone of predetermined known volume and a second zone with portions of the holder disposed around the first and second zones of said capillary comprising: filling said capillary tube with a liquid mixture; sealing the capillary tube at the open outer end of the second zone; mounting removable shield means on said holder, said shield means including air venting means disposed around the inner surface of the open end; separating the liquid mixture so that the first zone of said capillary is completely filled with a liquid sample; then severing the capillary tube at the weakened point and removing the second zone from said holder whereby a precise known voLume of liquid sample is disposed in the first zone and is ready for subsequent testing.

Claim 13

A method for separating a precise known volume of liquid contained in a disposable apparatus having a capillary tube mounted in a holder, said capillary tube having a weakened point formed between the ends thereof so as to form a first zone of predetermined known volume and a second zone with portions of the holder disposed around the first and second zones of said capillary comprising: filling said capillary tube with a liquid mixture; sealing the capillary tube at the open outer end of the second zone; mounting removable shield means on said holder, said shield means including air venting means disposed around the inner surface of the open end; separating the liquid mixture so that the first zone of said capillary is completely filled with a liquid sample; then severing the capillary tube at the weakened point and removing the second zone from said holder whereby a precise known voLume of liquid sample is disposed in the first zone and is ready for subsequent testing.

Claim 17

The method of separating a predetermined amount of a first component comprising a liquid fraction obtained from blood and mixing a predetermined amount of a second liquid with said first liquid to obtain a predetermined ratio of mixture, said method comprising: filling a capillary tube with blood comprising a mixture of light and heavy components; sealing an end of said capillary tube; separating the blood into its light and heavy component fractions in said capillary tube; severing the capillary tube into two segments comprising a first segment containing a predetermined amount of said light component fraction and a second zone containing heavy component fraction material; said first segment being mounted on a support means having means for coupling to a resilient container; mixing the predetermined amount of light component fraction with a predetermined amount of said second liquid in said container by first squeezing said container before coupling said support means to said container and then releasing said container and then alternately squeezing and releasing said container to remove all of said first liquid from said capillary tube to obtain a predetermined ratio mixture.

Claim 18

The method of separating a predetermined amount of a first component comprising a liquid fraction obtained from blood and mixing a predetermined amount of a second liquid with said first liquid to obtain a predetermined ratio of mixture, said method comprising: filling a capillary tube with blood comprising a mixture of light and heavy components; sealing an end of said capillary tube; separating the blood into its light and heavy component fractions in said capillary tube; severing the capillary tube into two segments comprising a first segment containing a predetermined amount of said light component fraction and a second zone containing heavy component fraction material; said first segment being mounted on a support means having means for coupling to a resilient container; mixing the predetermined amount of light component fraction with a predetermined amount of said second liquid in said container by first squeezing said container before coupling said support means to said container and then releasing said container and then alternately squeezing and releasing said container to remove all of said first liquid from said capillary tube to obtain a predetermined ratio mixture.

Claim 20

The method of separating a plasma or serum from blood as a first component and mixing a predetermined volume of said first component with a predetermined volume of a second liquid to obtain an accurate ratio of mixture, said method employing an assembly including a capillary tube with a weakened region adapted for breaking and located at a rigid support portion of a holder member, said holder member adapted to also support two removable shield members having venting means and enclosing the opposite ends of said capillary, said weakened region being adapted for breaking said capillary into a first segment of predetermined volume for plasma or serum and a second segment for packed red cells to be discarded, with the shield enclosing the second segment also enclosing capillary sealing means, said holder member adapted to be coupled in sealing engagement with a resilient container holding said second liquid, the said method comprising the steps of: removing said shields from said holder while grasping the assembly by said holder to avoid contaminating the capillary tube; filling the capillary tube with blood; sealing the outer end of the second segment of the capillary tube and enclosing said second segment by coupling one of said shields to the holder; wiping off overflow blood at the open end of the first segment of the capillary tube; enclosing and protecting the first segment of the capillary tube by coupling the other shield to the holder; centrifuging the blood to separate it in the capillary into plasma or serum and to completely fill the first segment and part of the second segment with plasma or serum while forcing all of the red cells into the second segment of the capillary; applying a force normal to the assembly to cause the shield enclosing said second segment to move and contact the capillary tube so as to break the capillary at its weakEned region while maintaining the capillary in uncontaminated condition while subjecting the assembly to breaking stresses without physically contacting the capillary; maintaining atmospheric conditions within the assembly by the venting means formed on said shields while the assembly is in use and prior to mixing with said second liquid to obviate volumetric changes due to changes in pressure caused when said shield is being coupled to or removed from said holder; removing the shield enclosing said second segment of the capillary and then removing said second segment; removing the shield enclosing said first segment; squeezing the resilient container to reduce its volumetric capacity; coupling the resilient container to said holder; releasing the resilient container to suck the predetermined volume of plasma or serum into the resilient container to mix with the predetermined volume of the second liquid contained therein; and alternately squeezing and releasing the resilient container to thoroughly rinse said first segment and thoroughly mix the two liquids in an accurate predetermined ratio.

Claim 21

The method of separating a plasma or serum from blood as a first component and mixing a predetermined volume of said first component with a predetermined volume of a second liquid to obtain an accurate ratio of mixture, said method employing an assembly including a capillary tube with a weakened region adapted for breaking and located at a rigid support portion of a holder member, said holder member adapted to also support two removable shield members having venting means and enclosing the opposite ends of said capillary, said weakened region being adapted for breaking said capillary into a first segment of predetermined volume for plasma or serum and a second segment for packed red cells to be discarded, with the shield enclosing the second segment also enclosing capillary sealing means, said holder member adapted to be coupled in sealing engagement with a resilient container holding said second liquid, the said method comprising the steps of: removing said shields from said holder while grasping the assembly by said holder to avoid contaminating the capillary tube; filling the capillary tube with blood; sealing the outer end of the second segment of the capillary tube and enclosing said second segment by coupling one of said shields to the holder; wiping off overflow blood at the open end of the first segment of the capillary tube; enclosing and protecting the first segment of the capillary tube by coupling the other shield to the holder; centrifuging the blood to separate it in the capillary into plasma or serum and to completely fill the first segment and part of the second segment with plasma or serum while forcing all of the red cells into the second segment of the capillary; applying a force normal to the assembly to cause the shield enclosing said second segment to move and contact the capillary tube so as to break the capillary at its weakEned region while maintaining the capillary in uncontaminated condition while subjecting the assembly to breaking stresses without physically contacting the capillary; maintaining atmospheric conditions within the assembly by the venting means formed on said shields while the assembly is in use and prior to mixing with said second liquid to obviate volumetric changes due to changes in pressure caused when said shield is being coupled to or removed from said holder; removing the shield enclosing said second segment of the capillary and then removing said second segment; removing the shield enclosing said first segment; squeezing the resilient container to reduce its volumetric capacity; coupling the resilient container to said holder; releasing the resilient container to suck the predetermined volume of plasma or serum into the resilient container to mix with the predetermined volume of the second liquid contained therein; and alternately squeezing and releasing the resilient container to thoroughly rinse said first segment and thoroughly mix the two liquids in an accurate predetermined ratio.