US 12,261,033 B2
Apolipoprotein e isotype detection by mass spectrometry
Darren Weber, Rancho Santa Margarita, CA (US); and Nigel Clarke, Vista, CA (US)
Assigned to Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed by Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed on Jan. 23, 2024, as Appl. No. 18/419,850.
Application 18/419,850 is a continuation of application No. 17/839,329, filed on Jun. 13, 2022, granted, now 11,929,243.
Application 17/839,329 is a continuation of application No. 16/051,171, filed on Jul. 31, 2018, granted, now 11,361,953.
Claims priority of provisional application 62/539,478, filed on Jul. 31, 2017.
Prior Publication US 2024/0222102 A1, Jul. 4, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 33/68 (2006.01); B01D 15/16 (2006.01); B01D 15/20 (2006.01); B01D 15/42 (2006.01); G01N 30/16 (2006.01); G01N 30/32 (2006.01); H01J 49/00 (2006.01); H01J 49/42 (2006.01)
CPC H01J 49/0045 (2013.01) [B01D 15/163 (2013.01); B01D 15/203 (2013.01); B01D 15/424 (2013.01); G01N 30/16 (2013.01); G01N 30/32 (2013.01); G01N 33/68 (2013.01); H01J 49/4215 (2013.01); G01N 2030/324 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for determining the apolipoprotein E (ApoE) phenotype in a sample comprising cerebrospinal fluid, plasma, or serum, said method comprising:
(a) digesting ApoE prior to purification, wherein the digesting comprises trypsin or microwave digestion;
(b) purifying ApoE in the sample;
(c) ionizing ApoE in the sample to produce one or more ion(s) of ApoE;
(d) detecting the ion(s) from step (c) by mass spectrometry; and
(e) determining the phenotype of ApoE allele(s) present in the sample from the ions detected in step (d), wherein the phenotype determined is ApoE2/ApoE2, ApoE2/ApoE4, ApoE3/ApoE3, ApoE3/ApoE4, or ApoE4/ApoE4; and
wherein:
the ApoE2/ApoE2 phenotype is determined by the presence of a fragment ion(s) having a mass/charge ratio selected from the group consisting of 665.72±0.5, 835.93±0.5, 866.99±0.5 and 982.08±0.5;
the ApoE2/ApoE4 phenotype is determined by the presence of a fragment ion(s) having a mass/charge ratio selected from the group consisting of 374.42±0.5, 502.55±0.5, 649.74±0.5, 665.72±0.5, 835.93±0.5; 866.99±0.5, 892.96±0.5, and 982.08±0.5;
the ApoE3/ApoE3 phenotype is determined by the presence of a fragment ion(s) having a mass/charge ratio selected from the group consisting of 374.42±0.5, 502.55±0.5, 866.99±0.5 and 982.08±0.5;
the ApoE3/ApoE4 phenotype is determined by the presence of a fragment ion(s) having a mass/charge ratio selected from the group consisting of 374.42±0.5, 502.55±0.5, 649.74±0.5, 866.99±0.5, 892.96±0.5, and 982.08±0.5; and
the ApoE4/ApoE4 phenotype is determined by the presence of a fragment ion(s) having a mass/charge ratio selected from the group consisting of 374.42±0.5, 502.55±0.5, 649.74±0.5, and 892.96±0.5.