Capillary Blood Collection Container Assembly for Low Dead Volume
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Solution Overview
Problem
Conventional blood collection containers suffer from inefficiencies in specimen flow, leading to significant sample wastage and exposure of medical practitioners, and are not compatible with standard diagnostic instrumentation.
Innovation Solution
A container assembly with a hollow inner member and closure design that utilizes capillary channels and a recessed area to enhance fluid flow, along with a collector body featuring capillary channels and a penetrating needle cannula for efficient sample collection and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional capillary collection devices use straight-walled collection cavities without flow-enhancing features, then the device structure is simple, but significant sample is trapped on the sidewall due to surface tension during collection and transfer
Solution Approach 1:
The collection cavity is designed with a curved, rounded bottom instead of straight walls, creating a funnel-shaped geometry that directs blood flow toward the aspiration hole. This curvature eliminates dead volume areas where sample would otherwise be trapped by surface tension, while maintaining manufacturing simplicity through molded construction.
Solution Approach 2:
The collection device is divided into functional zones: a collection area for initial blood accumulation, a transition zone with curved walls for flow direction, and an aspiration zone with the hole for instrument access. This segmentation optimizes each zone's function while collectively reducing sample wastage.
2Loss of substance
If conventional collection containers are sealed by a flat-bottomed cap assembly, then the sealing is simple, but dead volume sample is trapped within the collection cavity during transfer
Solution Approach 1:
The cap assembly's bottom surface is designed with a curved, recessed geometry that mirrors the collection cavity's shape. This curved sealing surface ensures complete contact with the cavity bottom, eliminating dead volume pockets where sample would be trapped, while the overall cap structure remains simple and moldable.
Solution Approach 2:
The cap assembly features a localized curved sealing surface at its bottom that interfaces with the collection cavity, while the rest of the cap maintains a simple cylindrical structure. This localized complexity at the sealing interface prevents dead volume without significantly increasing overall device complexity.
3Quantity of substance
If conventional collection containers are designed without flow-directing features, then manufacturing is simple, but a greater volume of sample must be collected to account for wastage
Solution Approach 1:
The funnel-shaped collection cavity with curved walls is designed to be formed in a single molding operation, integrating the flow-directing geometry into the basic container shape. This approach reduces the volume of sample needed by eliminating dead space, while the molding process maintains manufacturing simplicity without requiring complex assembly steps.
4Object-affected harmful factors
If conventional collection containers lack structured features for direct withdrawal, then the container design is simple, but exposure of medical practitioners to specimen during sampling increases
Solution Approach 1:
The collection cavity is designed with a standardized aspiration hole configuration that is compatible with multiple diagnostic instrument types. This universal interface allows direct instrument insertion into the cavity for sample withdrawal, eliminating the need for practitioners to manually access or manipulate the sample, thereby reducing exposure risk while maintaining structural simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces sample wastage, enhances compatibility with diagnostic instrumentation, and minimizes exposure to medical practitioners by optimizing fluid flow and collection efficiency.
Implementation Method 1
The closure distal end defines a recessed area shaped to direct fluid under capillary action to the at least one capillary channel in the inner member
Implementation Method 2
The hollow inner member is disposed within the outer container and has an inner surface defining at least one capillary channel
Data Source
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AI summary
A container assembly is disclosed including an outer container, a hollow inner member, and a closure. The outer container has a closed bottom, an open top, and a sidewall extending therebetween. The hollow inner member is disposed within the outer container and has an inner surface defining at least one capillary channel. The inner member includes a first end adjacent to the open top of the outer container and has an outer periphery seated against the sidewall of the outer container. The closure has a proximal end and a distal end. The closure proximal end is seated at least partially within the first end of the inner member to seal the outer container and inner member and define a fluid collection chamber. The closure distal end defines a recessed area shaped to direct fluid under capillary action to the at least one capillary channel in the inner member.