Method and apparatus for acquiring blood for testing

Abstract

A blood sampling device is provided having holder with a manipulating end and an absorbent probe on the opposing end. The probe is of hydrophilic polymer sized to directly absorb a predetermined volume of up to about 30 microliters of blood. Ribs on the holder position the probe within a compartment of a container to prevent contact with the container. The ribs also position the probe within extraction wells.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The application claims the benefit under 35 U.S.C. §119(e) to Provisional Patent Application No. 61 / 555,956 filed Nov. 4, 2012, titled METHOD AND APPARATUS FOR ACQUIRING BLOOD FOR TESTING, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]This application relates to a method apparatus for sampling blood for use in testing for either research or for diagnostic use.[0003]Multiple blood samples are used for clinical trials for pharmacokinetic analyses. These samples are often collected by sampling whole blood freezing and then processing the frozen blood later. Frozen blood requires a 200-250 ul sample of blood to be taken. This sample size limits the number of time-points which can be taken from a single animal due to the limited blood volume of small animals such as rats. Furthermore small volumes of blood samples are desired when dealing with critically ill patients. Moreover, there are hig...

AI Technical Summary

Benefits of technology

This patent describes a device that can collect and absorb biological fluids, like blood, for analysis. The device has an absorbent probe that can be easily dried and shipped. The absorbent probe is designed to wick up the fluid quickly and uniformly, and is made of a material that can absorb the same volume of fluid even when there is excess fluid. The holder allows for easy manipulation of the absorbent probe, and the absorbent probe can be placed against a blood sample or blood drop(s) to absorb the fluid. The volume of fluid absorbed is proportional to the volume of the absorbent probe. The device can be used with automated equipment and pipettors for easy manipulation. The conical shape of the absorbent probe helps wick the sample quickly and uniformly, and it absorbs a predetermined volume of blood during the sampling process. The absorbent probe can be placed in a liquid solvent to extract the analytes of interest, and the sample can then be further processed or analyzed. The device simplifies the sample matrix for further analysis.

Problems solved by technology

This sample size limits the number of time-points which can be taken from a single animal due to the limited blood volume of small animals such as rats.

Moreover, there are high costs involved with the freezing transportation and processing of whole blood.

When a card is used for direct sample collection from a wound (e.g. a neonatal heel prick or a finger prick) there is risk for collection of too much blood on the card which will lead to an overlapping of samples from the spots.

This will lead to difficulty in obtaining a sub-punch from the card that is representative of the entire spot.

Additionally, various chemical treatments of card materials can lead to separation of the PCV and serum during the drying process leading to non-homogenous sampling.

There are drawbacks, however, to the downstream processing of blood spots.

It is difficult to sample precise volumes using traditional glass capillaries, particularly directly from an animal or patient blood bolus.

While use of micropipettes (15 ul sample) can successfully create accurate spot volumes in carefully controlled settings, in practice these have proven to be unreliable.

Another drawback with the punching technique is that it relies on a constant sample viscosity in the expectation that the sample will spread uniformly on the sample card.

Unfortunately, viscosity varies significantly because of differing hematocrit (Ht or HCT) or packed cell volume (PCV) levels in the blood.

As internal standards are sprayed onto the spotted blood this could result in a 45% error in quantitation.

A further problem is that the blood is placed in marked areas on the cards, but often the person sampling the blood misses the mark and blood goes outside the marked area, making it difficult to accurately locate the circular punch over the blood spot.

Even if the blood spot is centered in the card, the person punching the card may not center the punch, resulting in variable sample size.

Further, the punching often shears the card and that often shakes dried blood loose, and if the punch cuts across a portion of the blood spot that also causes dried blood to be ejected into the air or work area.

Moreover, the blood spots are placed on rectangular cards which are difficult to manipulate by automated equipment, thus requiring extensive, expensive and time consuming manual handling and processing.

Automated handling equipment can be acquired for the specially shaped cards, but it is custom made, expensive, and of limited application.

Images