Evaluation of co‐oximetry for the measurement of methemoglobin in rainbow trout (<i><scp>O</scp>ncorhynchus mykiss</i>) and values in 3 salmonid species
Bibliographic record
Abstract
BACKGROUND: Methemoglobin (metHb) is oxidized hemoglobin that cannot reversibly bind oxygen, and concentrations in healthy fish have been reported to be 0.6-24.8% compared with 0-3% in healthy mammals. In fish, metHb has been measured using spectrophotometric methods using potassium cyanide (KCN), but not using co-oximetry, which is the preferred method for human samples. OBJECTIVES: The aims of this study were to evaluate co-oximetry as a method for measuring metHb in Oncorhynchus mykiss, compare co-oximetry with a KCN spectrophotometric method, and establish reference values for metHb concentrations as measured using co-oximetry in O mykiss, Salmo salar, and Salvelinus fontinalis. METHODS: Blood samples from healthy female O mykiss, female S salar, and female and male S fontinalis were prepared by separation and washing of erythrocytes in Tris/NaCl/EDTA buffer followed by lysis in Tris/EDTA buffer. MetHb concentrations were measured using an IL-682 co-oximeter. Moderate and high metHb concentrations were produced in vitro using NaNO(2). RESULTS: At low concentrations of methemoglobin, CVs for intraday precision were 10.3% and 53.9% using co-oximetry and the KCN spectrophotometric method, respectively. The CV for interday precision using co-oximetry was 11.9%. MetHb concentrations were stable in whole blood stored at 4°C for 7 days. MetHb concentrations were linear up to 58.2% (r = .99) using co-oximetry and 27.5% (r = .94) using the KCN method. The lower limit of detection for metHb was 0.02 g/dL using co-oximetry. Reference values for metHb concentrations using co-oximetry in O mykiss, S salar, and S fontinalis (n = 40 of each species) were 0.6-1.8%, 1.1-1.9%, and 1.1-4.0%, respectively. CONCLUSIONS: Co-oximetry can be used to measure methemoglobin in blood from fish, in particular in O mykiss, and is better than the KCN spectrophotometric method. Reference values for methemoglobin concentrations in O mykiss, S salar, and S fontinalis are similar to those in mammals.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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 source (direct Gemma or distilled Codex), 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".