at relatively low risk for chd pattern a lipoproteins are characterized by ldl particles larger median size of u02dc 22 5 nm versus u02dc 20 8 nm than those obtained from individuals at higher risk for coronary heart disease i e pattern b individuals additionally pattern a lipoproteins are characterized by a population of hdl particles that generally shows several subtypes these subtypes are revealed by several peaks in the hdl region of u02dc 7 13 nm for pattern a spectra the vertical line at approximately 8 9 nm indicates the principal hdl peak for patients with pattern a b and intermediate pattern ab the pattern a spectra are easily discerned by observing a second hdl peak at approximately 11 nm with these characteristics in mind traces 510 520 and 530 are low risk type a patterns the peak in the ldl population of particles for pattern b individuals is smaller by several nanometers than ldl particles from pattern a individuals the shift from pattern a to pattern b is represented approximately by the vertical lines drawn through the ldl peaks at approximately 20 8 nm dashed and 22 5 nm solid the hdl particles from pattern b individuals shown in traces 550 and 560 generally show less heterogeneity here the hdl peaks for pattern b patterns show only one sharp principal peak as expected thus the ion mobility measurements agree with gradient gel determinations and provide an alternative measurement method for assessing chd still referring to fig5 trace 540 represents a patient with an intermediate type ab pattern this trace 540 shows an.