US 11,885,780 B2
Methods for detecting chromogranin a by mass spectrometry
Darren Weber, Laguna Niguel, CA (US); Michael P. Caufield, San Clemente, CA (US); Michael McPhaul, Capistrano Beach, CA (US); Scott Goldman, Laguna Niguel, 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. 24, 2022, as Appl. No. 17/582,956.
Application 17/582,956 is a continuation of application No. 16/355,300, filed on Mar. 15, 2019, granted, now 11,231,401, issued on Jan. 25, 2022.
Claims priority of provisional application 62/644,210, filed on Mar. 16, 2018.
Prior Publication US 2022/0163494 A1, May 26, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 30/86 (2006.01); G01N 30/72 (2006.01); G01N 33/74 (2006.01); G01N 30/00 (2006.01); G01N 30/02 (2006.01)
CPC G01N 30/8675 (2013.01) [G01N 30/7266 (2013.01); G01N 33/74 (2013.01); G01N 2030/009 (2013.01); G01N 2030/027 (2013.01); G01N 2333/635 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method for determining the amount of chromogranin A (CgA) in a sample, said method comprising:
(a) purifying CgA in the sample;
(b) ionizing CgA to produce one or more ion(s) of CgA detectable by mass spectrometry;
(c) determining the amount of the ion(s) from step (b) by mass spectrometry, comprising measuring the amount of a precursor ion having a mass-to-charge ratio of 729.6±0.5, wherein the amount of ions is related to the amount of CgA in the sample, wherein the limit of quantitation of the method is less than or equal to 50 ng/mL, and
(d) correlating the amount of CgA in the sample to the amount of the precursor ion measured in step (c).