Meet us at AACC 2018 in Chicago
We will be participating the 2018 AACC Annual Meeting & Clinical Lab Expo. The exhibition will be on July 31 - August 2 in Chicago.
If you or a representative of your company is planning to attend, we would welcome the opportunity to meet with you. Send e-mail to hytest(at)hytest.fi to book a meeting.
You are warmly welcome to visit our booth #3948 at any time. Our team is looking forward to seeing you in Chicago!
Read more about the conference here. See you soon in Chicago!
Please also note that we are presenting the following posters at AACC this year:
Time: Tuesday, July 31, 9:30 AM – 5:00 PM
See all poster sessions here.
1. A-078 “NT-proBNP assays that are based on antibodies which are specific to nonglycosylated regions of NT-proBNP display a similar diagnostic accuracy in distinguishing heart failure patients compared to the Roche NT-proBNP assay”
Background: N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) is
a useful blood biomarker for the diagnosis of heart failure (HF). NT-proBNP is O-glycosylated
within the central part and present in the circulation as a pool of molecules
with different glycosylation levels. An automated NT-proBNP immunoassay manufactured
by Roche is widely used for NT-proBNP measurements. This assay employs
monoclonal antibodies (mAbs) that are specific to the epitopes 27-31 and 42-46 in the
central region of NTproBNP. One of the mAbs is specific to the partially glycosylated
region of NT-proBNP as the epitope 42-46 comprises Ser44, which is modified by
glycosidic residues. The presence of O-glycans at this site makes NT-proBNP undetectable
by the Roche NT-proBNP assay due to the steric hindrance. In light of this,
the assay is able to detect only the NT-proBNP fraction that is nonglycosylated at the
42-46 region and not the “total” NT-proBNP, i.e. both glycosylated and nonglycosylated
subfractions. Since O-glycosylation tends to be heterogeneous, its pattern and
extent might vary significantly among individuals and this could in turn impact the
clinical value of NT-proBNP measurements by glycosylation-sensitive NT-proBNP
assays. We have developed an alternative type of NT-proBNP immunoassays that are
not affected by analyte glycosylation and are able to measure the concentration of
the “total” NT-proBNP. The aim of this study was to compare the diagnostic accuracy
of measurements of the “total” NT-proBNP (by two prototype immunoassays)
with measurements of NT-proBNP that is nonglycosylated at Ser44 subfraction of NTproBNP
(by the Roche NT-proBNP assay) in distinguishing HF from non-HF patients.
Methods: NT-proBNP levels were measured by two HyTest’s prototype NT-proBNP
assays (capture mAb - detection mAb: 29D125-12 - NT3425-32 and 15C467-73 - 13G1215-20) and the Roche NT-proBNP assay (automated Roche Cobas e 411 analyzer) in
EDTA-plasma samples that were obtained from 51 patients who had been diagnosed
with HF and 53 healthy individuals (age-matched). HyTest’s prototype NT-proBNP
assays were linear in the range of 20 to 80,000 ng/L and the detection limits were
5-10 ng/L. Recombinant nonglycosylated NT-proBNP 1-76 (HyTest, produced
in E. coli) was used as a calibrator in the prototype NT-proBNP assays. The diagnostic
accuracy of the assays was analyzed by the comparison of the ROC curves.
Results: ROC-AUC for the prototype assays 29D125-12 - NT3425-32 and 15C467-73 - 13G1215-20 were 0.951/0.946 (sensitivity 0.86/0.84 and specificity 0.93/0.98 respectively)
compared to 0.965 (sensitivity 0.86 and specificity 0.98) for the Roche NTproBNP
assay. Differences were statistically insignificant (p-value = 0.365/0.369).
Conclusion: NT-proBNP immunoassays that are based on antibodies which are specific
to nonglycosylated regions of the NT-proBNP molecule are expected to have at
least a similar clinical value for HF diagnosis as the Roche NT-proBNP assay that
detects only a subfraction of endogenous NT-proBNP. Taking into account the known
high variability in levels and site occupancy of O-glycosylated proteins, we suggest
that immunoassays which measure “total” NT-proBNP levels might be advantageous
for HF diagnostics and/or therapy monitoring in certain groups of patients and disease
states due to their ability to detect endogenous NT-proBNP independently of its
2. A-093 “Human cardiac TnI degradation and antibody selection for the assay development”
Background: The measurement of cardiac troponin I (cTnI) in blood is one of the most trusted methods of acute myocardial infarction (AMI) diagnosis. However, in spite of a long history of this biomarker in clinical practice, the selection of antibodies for new generations of cTnI assays remains a complex task. Over the last decade it was shown that the samples of some patients contain autoantibodies that negatively interfere with most of the immunoassay mAbs which are specific to the central (~40-130 amino acid residues, aar) fragment of cTnI (which is considered to be the most stable part of the cTnI molecule). In the current study we aimed: a) to analyze the dynamics of cTnI degradation after AMI, and b) to border cTnI proteolytic fragments that are presented in the circulation of AMI patients in order to determine the epitopes of antibodies that are not significantly influenced by the proteolytic degradation.
Methods: Serial blood samples were collected from 66 patients over a period of 1-36 hours following the onset of AMI, both before and after stenting. cTnI and its fragments were studied by Western blotting and fluoroimmunoassay analysis.
Results: In the blood of all AMI patients, cTnI was presented by an intact molecule and 11 major fragments with relative molecular masses of 14-24 kDa. Stenting neither affected the repertoire nor the ratio of different cTnI fragments. The ratio of full sized cTnI and its fragments did not change considerably within the first 36 hours after the onset of AMI. mAbs with the epitopes located between ~23-196 aar recognized more than 80% of all detected cTnI.
Conclusion: The composition of cTnI fragments in the circulation is mainly constant within the first 36 hours following AMI. More than 80% of all detected fragments comprise 23-196 aar of cTnI which enables the utilization in immunoassays antibodies that are specific to the regions 23-40 and/or 140-196 that are only mildly affected by autoantibody interference.