The highest quality anti-mite fabrics were described by doctors as:
Tightly woven fabrics are derived from twisted cotton or synthetic fibres perpendicular to each other and having either a regular, systematised bi- or tri-axial weaving pattern. Thread count represents the coarseness or fineness of a fabric and is defined by the number of horizontal (warp or lengthwise) and vertical (weft or widthwise) threads in one square inch of the fabric.
Tightly woven fabrics, measured by pore size, allow little space for mites to penetrate, however, if the pore size is measured between 2 - 10 microns, the fabric will block the mite and the majority of its allergens. Too small a pore size (under 6 microns) may cause reduced 'breathability'.
Anti-mite Covers: Potential Criteria for Materials Used Against Dust Mites. Vanna Mahakittikun , John Joseph Boitano Chulaluk Komoltri , Prapakorn Ninsanit, Teerapong Wangapai 'Textile Research Journal', 2009, 79: 436,443
Mite penetration of different Types of Material Claimed to be Mite-proof by he Siriraj Chamber Method, Mahakittikun V., Boitano J. J., Tovey E., Bunnag C., Ninsanit P., Matsumoto T., Andre C., 'J. Allergy Clin, Immunol.', 118, 1164-1168 (2006)