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Immunoassay determination of rapamycin: reliability of the method with respect to liquid chromatography mass spectrometric quantification
Author(s) -
Pieri Maria,
Capone Domenico,
Gentile Antonio,
Miraglia Nadia,
Leo Emilo,
Federico Stefano,
Basile Vincenzo,
Acampora Antonio
Publication year - 2007
Publication title -
clinical transplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 76
eISSN - 1399-0012
pISSN - 0902-0063
DOI - 10.1111/j.1399-0012.2007.00701.x
Subject(s) - reproducibility , chromatography , medicine , immunoassay , liquid chromatography–mass spectrometry , mass spectrometry , chemistry , immunology , antibody
Immunochemical assays represent a promising tool for quantification of immunosuppressants in organ transplanted patients, because they require small sample volumes and minimum sample pre‐treatment; nevertheless considerations about method specificity, sensitivity and reproducibility cannot be overlooked. The present paper investigates the reliability of using the immunoparticle enzyme immunoassay (MEIA) for the quantification of blood rapamycin (RAPA) levels in therapeutic drug monitoring of renal transplanted patients with respect to a validated liquid chromatography tandem mass spectrometric (LC/ESI‐MSMS) method, used as reference. Linearity of MEIA was tested over the range 0.0–30.0 ng/mL, with accuracy and precision within acceptable limits. Fifty‐two blood samples were collected from 42 renal transplanted patients and analyzed simultaneously by both methods. The Pearson’s regression analysis gave the following parameters: correlation equation [RAPA] MEIA = 1.330 + 0.776 [RAPA] LC/ESI‐MSMS , r = 0.8526, SD = 1.778, p < 0.0001. The obtained average rapamycin concentration was 8.8 ± 3.4 ng/mL using MEIA and 9.6 ± 3.7 ng/mL for LC/ESI‐MSMS, with an overall underestimation of about 6% of the immunoenzymatic test. Accuracy of MEIA ranged from −33% to 36% with respect to the reference mass spectrometric method. Although immunoenzymatic test represents a fast and sufficiently accurate method for its use in clinical practice, specificity of the assay is still not sufficiently investigated and reference methods and/or Proficiency Testing Scheme should be used as external control.