title: Variability in sputum sol phase proteins in chronic obstructive bronchitis. The value of using albumin for standardization.
abstract: The variability of sputum sol phase proteins was studied in 27 patients with stable chronic obstructive bronchitis. Within individual patients (n 1/2 11), variability over 5 consecutive days was similar for each of 4 proteins studied: average coefficient of variation (CV) for albumin was 39.8% for alpha 1-antitrypsin (alpha 1AT), 32.1%, for alpha 1-antichymotrypsin (alpha 1ACh), 26.6%, and for immunoglobulin A (IgA), 35.1%. The calculation of sputum-to-serum ratios did not affect this variability. Between patients (all patients studied on a single day) the variability of sputum sol phase proteins was greater (CV: albumin 1/2 84.5%, alpha 1AT 1/2 90.1%, alpha 1ACh 1/2 58.3%, and IgA 1/2 71.6%) and was also unaffected by the use of sputum-to-serum concentration ratios. "Standardization" for albumin reduced the average within-patient variability for sputum alpha 1AT (CV from 32.1 to 19.7%) but it had no effect on alpha 1ACh and IgA. However, although between-patient CV for sputum alpha 1AT was also reduced (from 90.1 to 53.4%, 2 p less than 0.01) it significantly increased for alpha 1ACh (from 58.3 to 86.0%, 2 p less than 0.05) and IgA (71.6 to 170.1%, 2 p less than 0.001), suggesting that such standardization may be inappropriate for these proteins.
mesh_terms: D000368:Aged; D000418:Albumins / Q000032:analysis*; D001798:Blood Proteins / Q000032:analysis; D001991:Bronchitis / Q000378:metabolism*; D002908:Chronic Disease; D002918:Chymotrypsin / Q000032:analysis / Q000037:antagonists & inhibitors; D003102:Colloids; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D008173:Lung Diseases, Obstructive / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000032:analysis*; D012015:Reference Standards; D013183:Sputum / Q000032:analysis*; D014361:Trypsin Inhibitors / Q000032:analysis; D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin / Q000032:analysis
chemical_list: D000418:Albumins; D001798:Blood Proteins; D003102:Colloids; D007071:Immunoglobulin A, Secretory; D011506:Proteins; D014361:Trypsin Inhibitors; D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin; D002918:Chymotrypsin