Evaluation of the Abbott IMx <sup>TM</sup> fluorescence polarization immunoassay and the Bio-Rad enzyme immunoassay for homocysteine: comparison with high-performance liquid chromatography
Bibliographic record
Abstract
We evaluated the precision, linearity and accuracy of the Abbott IMx and Bio-Rad (Axis) homocysteine assays. Both assays make use of S-adenosyl-homocysteine hydrolase and excess adenosine, to convert homocysteine to S-adenosylhomocysteine (SAH). A monoclonal anti-SAH antibody is then used to quantify SAH. The IMx assay measures the fluorescence polarization of a conjugated SAH analogue for the final analytical step, whereas the Bio-Rad method uses a microplate enzyme immunoassay (EIA) employing an anti-mouse antibody peroxidase conjugate. The Abbott procedure is completely automated whereas the Bio-Rad EIA is performed manually. Between-run coefficient of variation using commercial controls was 2.6% at 7 micromol/L, 2.5% at 13 micromol/L and 1.7% at 24 micromol/L for the Abbott method, and 19.7% at 6.4 micromol/L, 15.9% at 11.0 micromol/L and 14.5% at 23.4 micromol/L for the Bio-Rad method. Both assays correlated well with a high-performance liquid chromatography (HPLC) procedure for homocysteine: Bio-Rad EIA = 1.03HPLC + 1.0 micromol/L, r=0.98, s(y/x)=0.51; Abbott IMx = 1.02HPLC + 0.7 micromol/L, r=0.99, s(y/x) = 0.33. Both methods were linear up to 50 micromol/L homocysteine. The IMx assay had superior precision as well as the technological advantage of being completely automated. Both immunoassays exhibited greatly improved throughput compared with our existing HPLC method.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".