Automated prozone effect detection in ferritin homogeneous immunoassays using neural network classifiers

Kornel Papik, Bela Molnar, Peter Fedorcsak, Rainer Schaefer, Fridl Lang, Lydia Sreter, Janos Feher, Zsolt Tulassay

Research output: Contribution to journalArticle

9 Citations (Scopus)


The application of turbidimetric homogeneous immunoassays made the determination of several plasma components widely available. The sensitivity and accuracy of these assays are appropriate enough for routine laboratory use; however, in the case of many pathologically high concentration samples, prozone effect (high dose hook effect) can be observed, that leads to false-negative determination. Up to the present there are no cost-effective algorithms available for the safe detection of the prozone effect. Pathological serum ferritin values can be elevated up to 5000 ng/ml, while the measuring range covers only the 0-440 ng/ml range by a commercial assay. The determination of samples with ferritin concentration 1500 ng/ml results in false-negative because of the overlapping measuring range and prozone effect range. The prozone effect can be recognised by analysis of reaction kinetics after measurement. We have developed a neural network classifier system to analyse reaction kinetics of the measurements and check the prozone effect. One thousand five hundred determinations and 77 patient samples were used for neural network training and test. Using the trained neural networks, false-negative results can be filtered immediately after the determination, without re-run; thus, the sensitivity of plasma ferritin determination may become reliable enough, even in the case of high concentration samples. Applying this new technology, false-negative serum ferritin determinations can be avoided, thus even a relatively high hook effect rate (5-12% in different patient groups) can be handled safely.

Original languageEnglish
Pages (from-to)471-476
Number of pages6
JournalClinical Chemistry and Laboratory Medicine
Issue number4
Publication statusPublished - May 20 1999


  • Ferritin
  • High-dose hook effect
  • Neural networks
  • Prozone effect
  • Turbidimetry

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

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