The MTX FPIA
has shown 82.6% cross-reactivity with DAMPA in the method that uses polyclonal antibodies and 41.1% cross-reactivity in the method that uses monoclonal antibodies (7).
digoxin assay is linear to a serum digoxin concentration of 5.0 ng/mL with a sensitivity of 0.20 ng/mL.
In acidic citrate samples Hcy increased slowly at room temperature, reaching the level of significance after 6 h (FPIA
) and 24 h (HPLC), respectively.
The CV in the Abbott FPIA
assays exceeded 20% only at the lowest concentrations of PCP and BEG tested.
* Studies involving several laboratories should use methods with low bias (FPIA
, some GC-MS assays) and establish joint procedures for calibration.
For concentrations <500 [micro]g/L (n = 12; results for the year 2002), the mean CVs were 10% for the Emit and 6.0% for the FPIA
. The interlaboratory CV obtained with a whole blood sample to which 2000 [micro]g/L cyclosporin had been added was 7.9% for the Emit (n = 38) and 7.2% for the FPIA
(n = 30).
For example, the popular Abbott TDx FPIA
gave high results for phenytoin but low results for carbamazepine and valproate.
Stabilizing blood with 3-deazaadenosine interferes in the Abbott FPIA
assay for plasma homocyst(e)ine.
Immunologic screening of the urine samples was performed with two different immunoassays: the automated AxSYM analyzer (Abbott) with the Abbott fluorescence polarization immunoassay (FPIA
) Amphetamine/Methamphetamine II and the Mahsan-AM[P.sub.300] on-site test (Mahsan Diagnostika).
They include the microtiter plate enzyme immunoassay (12) and the fluorescence polarization immunoassay (FPIA
) on the Abbott IMx[R] analyzer (13).
On October 31, 2001, the patient's urine tested positive for cocaine metabolite (qualitative, >300 [micro]g/L) by fluorescent polarization immunoassay (FPIA
; Abbott Laboratories), but she denied abuse within the past several months.
We studied the stability of plasma tHcy measured by a fluorescence polarization immunoassay (FPIA
) in samples from 9 cystathionine [beta]-synthase (C[beta]S)-deficient homocystinuric patients and 13 healthy individuals.
The following digoxin methods were performed as suggested by the manufacturers: AxSYM MEIA II; IMx[R] MEIA II (singleton analyses; Abbott); TDx[R] fluorescence polarization immunoassay (FPIA
; singleton analyses; Abbott); Emit 2000[R] (bade Behring) on the Cobas Mira 5 system; Dimension[R] (bade Behring); aca[R] (bade Behring) on the aca SX (singleton analyses); TinaQuant[R] (Roche) on the Hitachi 912; Elecsys[R] (Roche) on the Elecsys 2020; and Vitros[R] slides (Ortho Clinical Diagnostics) on the Vitros 950.
Marker Type of assay AT Heparin cofactor activity against factor Xa PC Amidolytic assay with snake venom as activator PS Free antigen APC resistance APTT-based method without and with FV deficient plasma Confirmation of positive and borderline results by FV genotyping Dysfibrinogenemia Thrombin and reptilase times Parallel analysis of immunologic and functional fibrinogen Anti-phospholipid Phospholipid-dependent tests (i.e., KCT, antibodies dRVVT) and aCL antibodies Hyperprothrombinemia Prothrombin genotyping Hyperhomocysteinemia HPLC, FPIA
(b) Factor VIII Activity (clotting or amidolytic) or antigen measurement (a) Markers and types of assay listed here represent the authors' choice.
We report the observation of false-positive results obtained with the AxSYM (r) FPIA
Amphetamine/Methamphetamine II assay (Abbott), which is widely used to detect commonly abused amphetamine compounds in human urine.