Case Study: Touch Spot
Increasing patient compliance via an in-home, easy-to-use dried blood spot collection device
Chronic diseases and organ transplants require repeated blood tests, most often using venipuncture (blood draws) to monitor success of therapeutic interventions. However, repeated blood draws are painful, expensive, and interfere with daily activities. It has been found that once children who have had organ transplants reach their teenage years, compliance with coming into the lab every month to have their blood levels tested decreases. If they miss too many visits, and complications are not caught early, there is a risk that the body could reject the transplanted organ.
The research team at Oregon Health and Sciences University (OHSU) approached Simplexity with an idea to used dried blood spot (DBS) technology to create a medical device that could be used in the home to collect a precise volume of blood and the sample could be mailed in for analysis.
DBS methods, dropping a few drops of blood onto filter paper, have been used in newborn screening since the 1970s. However, the widespread use of DBS in infants and children for in-home use has been limited due to many constraints inherent in the DBS collection methodology. While DBS samples are adequate for qualitative assays, quantitative assays to measure drug levels and analytes in the blood require a precise volume of blood, which traditional DBS methods do not accomplish. Pictured below is a representative filter paper with dried blood spots collected. Clearly, the amount of blood deposited is not consistent across samples.
The Simplexity engineering team worked alongside OHSU researchers and physicians to develop the TouchSpotTM. The TouchSpotTM collects a precise volume of blood on a pre-cut filter paper disc by a method that eliminates the need to drip the blood, thus avoiding the problem of touching the filter paper. When the pre-cut disc is spotted with a capillary tube containing more blood than needed, the paper will saturate and blood will stop flowing. This achieves a homogenous distribution of blood on a consistent volume of filter paper from a single finger/heel prick.
- Can be easily used by patients of all ages and still works even if the skin touches the device.
- Collects an accurate and precise sample at home or on the go
- Is sent to lab via air mail for mass spectrometry analysis
- Determines the blood/drug levels independent of the hematocrit
- Eliminates touch failures associated with traditional method
Prototype devices were tested in a small user trial with healthy adult volunteers. The resulting blood spots collected were visually inspected. Additionally, liquid chromatography with tandem mass spectrometry (LC-MS/MS) was performed on the samples. While the sample size was small, the results yielded a precision of 6.6%, which is considered excellent.
Using an accurate and precise pre-cut disc makes TouchSpotTM superior to traditional DBS methods for precise volumetric blood collection. Thus, the applications for the TouchSpotTM far exceed the organ transplant or pediatric market, and may include:
- Infectious diseases such as HIV/AIDS or Ebola
- Chronic diseases such as epilepsy or cystic fibrosis
- Drug rehabilitation
- Veterinary medicine
- Remote testing in developing countries
The TouchSpotTM is an excellent example of how Simplexity collaborates with scientists and researchers. Simplexity performed all the engineering and microfluidics analysis to design the device, while OHSU provided scientific guidance, conducted the user test, and analyzed the results. Together, Simplexity engineers and OHSU researchers invented the method that accurately delivered a precise volume of blood to the pre-punched DBS filter paper, which is housed inside the TouchSpotTM. For this reason, representatives from both entities are listed as co-inventors on the patent, which is pending.