The frequency and significance of isolated hepatitis B core antibody and the suggested management of patients.
Bibliographic record
Abstract
1It may be the only serum marker of acute hepatitis B infection during the so-called “window phase” between disappearance of HBsAg and appearance of HBsAb. It may also represent a remote resolved infection with the decline of HBsAb to undetectable levels or ongoing chronic infection with HBsAg that is escaping detection, either because of low levels of HBsAg or because of mutations in the protein that render it undetectable using certain diagnostic assays. It rarely represents a false-positive test. Acute hepatitis B virus (HBV) infection is often recognized by its clinical presentation, and repeat testing after several weeks will generally detect the appearance of HBsAb. The other clinical possibilities are not easily distinguished on routine serological testing but may have important consequences, particularly in situations of chronic infection with no detection of HBsAg. Cost efficacy considerations led to a recent change in the routine heptatitis B screening algorithm at the Sir Mortimer B. Davis–Jewish General Hospital, a tertiary care, 637-bed teaching hospital in Montreal. Patients are now evaluated initially with serum HBcAb testing. A negative HBcAb test result is reported as HBV-negative, and a positive result is followed by testing for HBsAg and, if this result is negative, HBsAb. HBsAg-positive sera are tested for hepatitis B e antigen (HBeAg) and hepatitis B e antibody (HBeAb). Between June 1999 and March 2000, 4121 individual patients who were not pregnant were screened for HBV using HBcAb as the initial test. Of these, 3273 patients tested negative (79%), and 848 patients tested positive (21%) for HBcAb. Because there was an insufficient number of samples, 24 HBcAb-positive patients were excluded from further testing. Of the remaining 824 patients, 175 (21%) tested positive for HBsAg and 649 (79%) tested negative. The 649 HBsAg-negative patients were tested for HBsAb. Of these, 446 (69%) had a titre of more than 10 IU (positive), 81 patients (12%) had a titre of less than 1 IU (negative) and 122 patients (19%) had a value ranging between 1.0 and 10 IU (low level). Therefore, 81 (2.0%) of 4121 patients screened during this 10-month period had HBcAb as the only positive marker of infection. Among HBcAb-positive patients, at least 81 (10%) of 848 had both undetectable HBsAg and HBsAb. Isolated HBcAb has been reported in up to 20% of patients tested. 2–6
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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 | 0.001 |
| 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".