title: Serum insulin-like growth factor-1 measurement in the diagnosis and follow-up of patients with acromegaly: preliminary data.
abstract: Measurement of serum insulin-like growth factor-1 (IGF-I) is the current method for diagnosing and monitoring acromegaly. However, the use of commercially available kits needs to be validated. In our study, we have investigated the use of two different IGF-I immunoassays in patients already diagnosed with acromegaly. We compared a two-site immunoradiometric assay with ethanol-acid extraction (IRMA-DSL) and a solid-phase chemiluminescent immunometric assay (ICMA-IMMULITE), correlating the clinical finding with the biochemical results. A total of 102 samples (77 women and 25 men aged 18-79 years) were analyzed with the two different IGF-I assays. Sixty-four of samples had been taken from patients with acromegaly in different stages. Pearson regression showed a high correlation coefficient; otherwise, Bland and Altman analyses showed a mean difference of 177.6 ng/ml, with upper and lower limits of -183.5 and 538.7 ng/ml in the 102 samples studied. Normal serum IGF-I was found in 64 and 41.5% of patients with treated acromegaly when measured by ICMA and IRMA, respectively. In our study, IGF-I-ICMA had a better clinical correlation in patients with treated acromegaly. The reevaluation of current IGF-I immunoassays is necessary to correctly interpret treatment response in acromegalic patients and thus achieve a better correlation between clinical and biochemical results.
authors.forename: Mirtha
authors.initials: M
authors.lastname: Guitelman
authors.forename: Graciela
authors.initials: G
authors.lastname: Radczuk
authors.forename: Natalia García
authors.initials: NG
authors.lastname: Basavilbaso
authors.forename: Adriana
authors.initials: A
authors.lastname: Oneto
authors.forename: Armando
authors.initials: A
authors.lastname: Basso
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015592:Immunoradiometric Assay; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D007334:Insulin-Like Growth Factor I