Methaemalbumin: a diagnostic surrogate for methaemoglobinaemia and treatment with red cell exchange in a patient with thalassaemia
Bibliographic record
Abstract
A man in his 30s with alpha thalassaemia (four-alpha globin gene deletion) presented with 1 week of shortness of breath and 1 month of general malaise. Pulse oximetry monitoring revealed low peripheral oxygen saturation of approximately 80% despite maximal high-flow nasal cannula oxygen (fractional inspired oxygen 1.0-60 L/min flow). Arterial blood gas samples were chocolate brown in colour, with a low arterial partial pressure of oxygen of 197 mm Hg. This large oxygen saturation gap raised suspicion for methaemoglobinaemia. However, the patient's co-oximetry results were suppressed by the blood gas analyser and delayed a definitive diagnosis. A methaemalbumin screen was sent instead, which was positive at 65 mg/L (reference interval: <3 mg/L). Treatment with methylene blue was initiated but did not result in complete resolution of cyanosis. This patient had been red cell exchange dependent since childhood for thalassaemia. Therefore, an urgent red cell exchange was initiated overnight, leading to an improvement in symptoms and interpretability of co-oximetry results. This resulted in rapid improvement without residual sequelae or complications. We conclude that a methaemalbumin screen can be used as a surrogate test for prompt confirmation of diagnosis in lieu of co-oximetry in cases of severe methaemoglobinaemia or in cases with underlying haemoglobinopathy. Red cell exchange can allow prompt methaemoglobinaemia reversal, especially if methylene blue is only partially effective.
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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 | 0.000 | 0.000 |
| 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 | 0.000 | 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 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".