title: Determination of iron by the Ferrochem II: interference by tuberculostatics.
abstract: Iron levels in samples from certain treated tuberculous patients are underestimated by the Ferrochem II analyser. Of the tuberculostatic drugs examined for a possible interference, isoniazid, ethambutol, rifampicin, pyrazinamide and Rifater (a mixture of rifampicin, isoniazid and pyrazinamide), only pyrazinamide and Rifater (due to its pyrazinamide content) were associated with iron levels differing significantly (p < 0.001) from those of controls, with means of -317.2 and -185.6 mumol l-1 for pyrazinamide and Rifater respectively as against 9.91 mumol l-1 for the controls. The negative interference (I) due to pyrazinamide was independent of iron level in the samples but dependent on pyrazinamide concentration in the same (P) (r = 0.9993), I = -0.4380P-0.4276.
authors.affiliation: Servicio de Análisis Clínicos, Hospital Provincial de Santiago, La Coruña, Spain.
authors.forename: M E
authors.initials: ME
authors.lastname: San José
authors.forename: A
authors.initials: A
authors.lastname: Sarandeses
authors.forename: D
authors.initials: D
authors.lastname: Alvarez
authors.forename: L
authors.initials: L
authors.lastname: Valdés
authors.forename: B
authors.initials: B
authors.lastname: Chomón
authors.forename: M J
authors.initials: MJ
authors.lastname: Del Rio
mesh_terms: D000995:Antitubercular Agents / Q000097:blood*; D004338:Drug Combinations; D004563:Electrochemistry; D006801:Humans; D007501:Iron / Q000097:blood*; D007538:Isoniazid / Q000097:blood; D011718:Pyrazinamide / Q000097:blood; D012293:Rifampin / Q000097:blood; D013054:Spectrophotometry, Atomic
chemical_list: D000995:Antitubercular Agents; D004338:Drug Combinations; C087181:isoniazid, pyrazinamide, rifampin drug combination; D011718:Pyrazinamide; D007501:Iron; D007538:Isoniazid; D012293:Rifampin