Design and Characterization of a Novel Blood Collection and Transportation Device for Proteomic Applications

Clinical evaluation of patterned dried plasma spot cards to support quantification of HIV viral load and reflexive genotyping

Quantifying viral load, a key indicator required to achieve control and elimination of the HIV epidemic, requires cell-free plasma or serum to ensure measurements are not biased by proviral DNA contained in infected CD4 T lymphocytes. Plasma separation cards (PSC) collect and preserve a dried specimen, which makes them practical solutions for decentralized sample collection and transport in limited-resource settings. However, physiological variations in hematocrit levels can introduce significant variability in the quality of plasma generated by commercial PSCs and can lead to inaccurate test results and clinical decisions. In addition to hematocrit-dependent sampling, the Roche PSC, a standard for dried plasma collection, is known to induce considerable hemolysis, which further impacts specimen quality, concordance with liquid plasma, and the overall benefit of microsampling. We address these gaps with a patterned dried plasma spot (pDPS) card, which generates plasma with improved hematocrit independence and minimal hemolysis. This study directly compares pDPS cards to the Roche PSC to measure HIV viral load. Analysis of viral load from 75 donors revealed strong agreement in sensitivity, specificity, overall accuracy, and viral load band placement between devices, with quantitative metrics suggesting improved performance for pDPS cards. In reflexive genotyping, remnant dried blood from pDPS cards exhibited greater success than Roche PSC in amplification and sequencing (71% vs. 62%) and detecting drug resistance mutations (63% vs. 42%). Based on this performance, pDPS cards can be versatile across multiple analytical platforms, integrate seamlessly into existing clinical laboratory workflows, and aid clinicians in making accurate treatment decisions.

Use of a Novel Whole Blood Separation and Transport Device for Targeted and Untargeted Proteomics

BACKGROUND

There is significant interest in developing alternatives to traditional blood transportation and separation methods, which often require centrifugation and cold storage to preserve specimen integrity. Here we provide new performance findings that characterize a novel device that separates whole blood via lateral flow then dries the isolated components for room temperature storage and transport.

METHODS

Untargeted proteomics was performed on non-small cell lung cancer (NSCLC) and normal healthy plasma applied to the device or prepared neat.

RESULTS

Significantly, proteomic profiles from the storage device were more reproducible than from neat plasma. Proteins depleted or absent in the device preparation were shown to be absorbed onto the device membrane through largely hydrophilic interactions. Use of the device did not impact proteins relevant to an NSCLC clinical immune classifier. The device was also evaluated for use in targeted proteomics experiments using multiple-reaction monitoring (MRM) mass spectrometry. Intra-specimen detection intensity for protein targets between neat and device preparations showed a strong correlation, and device variation was comparable to the neat after normalization. Inter-specimen measurements between the device and neat preparations were also highly concordant.

CONCLUSIONS

These studies demonstrate that the lateral flow device is a viable blood separation and transportation tool for untargeted and targeted proteomics applications.

Advancements in clinical approaches, analytical methods, and smart sampling for LC-MS-based protein determination from dried matrix spots

Determination of proteins from dried matrix spots using MS is an expanding research area. Mainly, the collected dried matrix sample is whole blood from a finger or heal prick, resulting in dried blood spots. However as other matrices such as plasma, serum, urine, and tear fluid also can be collected in this way, the term dried matrix spot is used as an overarching term. In this review, the focus is on advancements in the field made from 2017 up to 2023. In the first part reviews concerning the subject are discussed. After this, advancements made for clinical purposes are highlighted. Both targeted protein analyses, with and without the use of affinity extractions, as well as untargeted, global proteomic approaches are discussed. In the last part, both methodological advancements are being reviewed as well as the possibility to integrate sample preparation steps during the sample handling. The focus, of this so-called smart sampling, is on the incorporation of cell separation, proteolysis, and antibody-based affinity capture.

Microsampling tools for collecting, processing, and storing blood at the point-of-care

In the wake of the COVID-19 global pandemic, self-administered microsampling tools have reemerged as an effective means to maintain routine healthcare assessments without inundating hospitals or clinics. Finger-stick collection of blood is easily performed at home, in the workplace, or at the point-of-care, obviating the need for a trained phlebotomist. While the initial collection of blood is facile, the diagnostic or clinical utility of the sample is dependent on how the sample is processed and stored prior to transport to an analytical laboratory. The past decade has seen incredible innovation for the development of new materials and technologies to collect low-volume samples of blood with excellent precision that operate independently of the hematocrit effect. The final application of that blood (i.e., the test to be performed) ultimately dictates the collection and storage approach as certain materials or chemical reagents can render a sample diagnostically useless. Consequently, there is not a single microsampling tool that is capable of addressing every clinical need at this time. In this review, we highlight technologies designed for patient-centric microsampling blood at the point-of-care and discuss their utility for quantitative sampling as a function of collection material and technique. In addition to surveying methods for collecting and storing whole blood, we emphasize the need for direct separation of the cellular and liquid components of blood to produce cell-free plasma to expand clinical utility. Integrating advanced functionality while maintaining simple user operation presents a viable means of revolutionizing self-administered microsampling, establishing new avenues for innovation in materials science, and expanding access to healthcare.

Direct Processing and Storage of Cell-Free Plasma Using Dried Plasma Spot Cards

Plasma separation cards represent a viable approach for expanding testing capabilities away from clinical settings by generating cell-free plasma with minimal user intervention. These devices typically comprise a basic structure of the plasma separation membrane, unconstrained porous collection pad, and utilize either (i) lateral or (ii) vertical fluidic pathways for separating plasma. Unfortunately, these configurations are highly susceptible to (i) inconsistent sampling volume due to differences in the patient hematocrit or (ii) severe contamination due to leakage of red blood cells or release of hemoglobin (i.e., hemolysis). Herein, we combine the enhanced sampling of our previously reported patterned dried blood spot cards with an assembly of porous separation materials to produce a patterned dried plasma spot card for direct processing and storage of cell-free plasma. Linking both vertical separation and lateral distribution of plasma yields discrete plasma collection zones that are spatially protected from potential contamination due to hemolysis and an inlet zone enriched with blood cells for additional testing. We evaluate the versatility of this card by quantitation of three classes of analytes and techniques including (i) the soluble transferrin receptor by enzyme-linked immunosorbent assay, (ii) potassium by inductively coupled plasma atomic emission spectroscopy, and (iii) 18S rRNA by reverse transcriptase quantitative polymerase chain reaction. We achieve quantitative recovery of each class of analyte with no statistically significant difference between dried and liquid reference samples. We anticipate that this sampling approach can be applied broadly to improve access to critical blood testing in resource-limited settings or at the point-of-care.