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Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding
Minoru Tomizawa1, Fuminobu Shinozaki1, Rumiko Hasegawa1
1Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
Insights
A blood urea nitrogen (BUN) threshold of 21.0 mg/dL can effectively distinguish between upper and lower gastrointestinal (GI) bleeding. This finding aids in diagnosing the source of GI bleeds.
Area of Science:
- Gastroenterology
- Clinical Diagnostics
Background:
- Distinguishing upper from lower gastrointestinal (GI) bleeding is crucial for appropriate patient management.
- Existing diagnostic methods can be invasive or time-consuming.
Purpose of the Study:
- To identify a biochemical marker that can reliably differentiate between upper and lower GI bleeding.
- To establish a specific threshold value for this marker.
Main Methods:
- Retrospective analysis of patient records from April 2011 to March 2014.
- Comparison of laboratory variables between patients with upper GI bleeding and lower GI bleeding using ANOVA.
- Logistic regression and Receiver-Operator Characteristic (ROC) analysis to determine diagnostic thresholds.
Main Results:
- Blood urea nitrogen (BUN) was significantly higher in patients with upper GI bleeding compared to lower GI bleeding (P = 0.0065).
- Logistic regression identified BUN as the strongest predictor for differentiating bleeding sources.
- ROC analysis determined a BUN threshold of 21.0 mg/dL with 93.0% specificity.
Conclusions:
- A blood urea nitrogen (BUN) level of 21.0 mg/dL is a specific threshold for distinguishing upper from lower gastrointestinal bleeding.
- This biochemical marker offers a potentially non-invasive method to aid in the initial assessment of GI bleeding.
Aim:
To distinguish upper from lower gastrointestinal (GI) bleeding.
Methods:
Patient records between April 2011 and March 2014 were analyzed retrospectively (3296 upper endoscopy, and 1520 colonoscopy). Seventy-six patients had upper GI bleeding (Upper group) and 65 had lower GI bleeding (Lower group). Variables were compared between the groups using one-way analysis of variance. Logistic regression was performed to identify variables significantly associated with the diagnosis of upper vs lower GI bleeding. Receiver-operator characteristic (ROC) analysis was performed to determine the threshold value that could distinguish upper from lower GI bleeding.
Results:
Hemoglobin (P = 0.023), total protein (P = 0.0002), and lactate dehydrogenase (P = 0.009) were significantly lower in the Upper group than in the Lower group. Blood urea nitrogen (BUN) was higher in the Upper group than in the Lower group (P = 0.0065). Logistic regression analysis revealed that BUN was most strongly associated with the diagnosis of upper vs lower GI bleeding. ROC analysis revealed a threshold BUN value of 21.0 mg/dL, with a specificity of 93.0%.
Conclusion:
The threshold BUN value for distinguishing upper from lower GI bleeding was 21.0 mg/dL.
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