Blood sample prep is one of the most important (and often overlooked) clinical diagnostic steps, especially in point-of-care blood testing. Test results are only as reliable as the sample tested – poorly handled samples can result in inaccurate measurements, misdiagnoses, ineffective and dangerous treatments, poor patient outcomes, and enormously excessive costs.


In typical lab workflows, blood plasma or serum is separated from blood cells using a laboratory centrifuge prior to running the test. This separation should occur within 1 to 2 hours of collection to minimize hemolysis and other contamination prevalent with unseparated blood samples.

Plasma and serum 1 to 2 hours of collectionHowever, conventional centrifugation is often not possible when samples are collected in remote settings such as a doctor’s office, drive-through testing location, mobile clinic, or the patient’s home.


New technologies are arising to address point-of-care sample prep challenges and expand widespread access to important blood tests.


  • Sandstone’s Torq Zero Delay Centrifuge System is an ultra-portable, fast, and easy-to-use centrifuge that can provide lab-quality plasma anywhere. The Torq ZDrive runs on 2 AA batteries and uses single-use discs (instead of blood tubes) in order to shrink the centrifuge into a device that literally fits in the palm of your hand and processes samples in just 2 to 5 minutes. Visit our shop for more information about the small volume capillary blood (finger stick) and larger volume venous blood (venipuncture) products available today.
  • Microfluidic techniques can be used to integrate sample prep directly into point-of-care analyzers such that whole blood samples can be tested directly. Promising technologies include surface acoustic waves (SAW), digital electrowetting, and centrifugal “lab on a disk” device While such approaches increase the cost and complexity of the analyzer and consumables, fully-integrated devices may be preferred for point-of-care applications requiring minimal user handling.
  • Innovations in dried microsampling are driving simple and cost-effective ways to collect and transport small volume blood samples. Traditional dried blood spots suffer from whole blood contamination, hematocrit bias, and sample dilution effects in reconstituting samples. Devices like plasma separation cards and dried blood swabs address some of these limitations to enable more reliable collection and transport of samples to centralized facilities without refrigeration.


Healthcare is increasingly relying on decentralized blood sample collection and testing in our post-Covid-19 world. Check out our shop or contact us below to learn more about how Sandstone’s Torq technology can accelerate your diagnostic needs.



  1. CLSI (2010) Procedures for the Handling and Processing of Blood Specimens for Common Laboratory Tests; Approved Guideline – Fourth Edition.
  2. Park J, Han DH, Park JK. Towards practical sample preparation in point-of-care testing: user-friendly microfluidic devices. Lab Chip. 2020 Apr 7;20(7):1191-1203. doi: 10.1039/d0lc00047g. Epub 2020 Mar 2. PMID: 32119024.
  3. Nayak S, Blumenfeld NR, Laksanasopin T, Sia SK. Point-of-Care Diagnostics: Recent Developments in a Connected Age. Anal Chem. 2017;89(1):102-123. doi:10.1021/acs.analchem.6b04630
  4. Collier N, Hewett C. PoC Diagnostics Innovation: Overcoming The Sample Prep Challenge. Diagnostics World. April 8 2020.
  5. Leslie Y. Yeoand James R. Friend Surface Acoustic Wave Microfluidics. Annual Review of Fluid Mechanics 2014 46:1, 379-406.
  6. Li J, Kim CC. Current commercialization status of electrowetting-on-dielectric (EWOD) digital microfluidics. Lab Chip. 2020 May 19;20(10):1705-1712. doi: 10.1039/d0lc00144a. PMID: 32338272.
  7. Hau Van Nguyen, Van Dan Nguyen, Huynh Quoc Nguyen, Tin Hoang Trung Chau, Eun Yeol Lee, Tae Seok Seo. Nucleic acid diagnostics on the total integrated lab-on-a-disc for point-of-care testing. Biosensors and Bioelectronics, Volume 141, 2019, 111466, ISSN 0956-5663, (

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