Researchers at the National Institute of Standards and Technology (NIST) have discovered a potential source of error when using acoustic waves to measure the properties of fluids such as blood. Their discovery raises the possibility of more accurate diagnostic tests for certain types of blood cancer, and more precise sorting of blood cells.

All acoustic waves, including ultrasound, create regions of alternating high and low pressure in a medium such as air, water, and other fluids such as blood. Researchers frequently use them to study the properties of small volumes of “microfluids,” those confined to vessels no wider than the thickness of a credit card.

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