Assessment of Short-Term Individual Variation of Osmolality Based on Serial Patient Measurements
Bibliographic record
Abstract
Objectives: Osmolality is a sensitive clinical measure of hydration status and the single best biomarker for assessment of hypertonic hypovolemia. Knowledge of expected combined analytical and biological variation in a physiologic state is important for assessment of the clinical significance of changes in serial patient measurements. Whereas analytical variation may be inferred from quality control data, estimates of biological variation have usually required collection of consecutive samples from healthy subjects and testing on a single run. This study is the first to derive the short-term biological variation (s b ) of plasma osmolality through statistical analysis of a large dataset of serial patient measurements. Methods: Plasma osmolality measurements by freezing point depression (Advanced Instrument Inc. 3320) from inpatients at a single university hospital over a 10-year period were data-mined. The standard deviation of differences (SDDs) for serial results separated into two-hour intervals (0-2h, 2-4h, 4-6h, and so on, up to 16 hours) were calculated for 134,940 paired intrapatient osmolalities. The graph of SDDs vs time interval was linear. The y intercept, y 0 provided by linear regression represents the sum of s b and short-term analytical variation (s a ): y 0 = ( sa2 + sb2 ) 1/2 . s a was obtained from quality control data. Results: Osmolality displayed a nearly normal distribution with a mean of 298 and median of 296 mmol/Kg. y 0 , s a , and s b were 3.27, 1.4, and 2.95, respectively corresponding to a short term biological variation of 1.0%. Conclusions: The data show a slightly lower biological variation of plasma osmolality than that provided by Westgard at 1.3% ( https://www.westgard.com/biodatabase1.htm ). It confirms that intraindividual variation in osmolality is tightly controlled.
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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 | 0.006 | 0.002 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".