« Previous Next » Annals of Emergency Medicine
Volume 55, Issue 2 , Pages 184-189 , February 2010

A Simple Quantitative Bedside Test to Determine Methemoglobin

Fathima Shihana, BSc
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
- Department of Pathology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
- Address for correspondence: Fathima Shihana, BSc, South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Sri Lanka; 94-081-4479822, fax 94-081-4479822
Dhammika Menike Dissanayake, MD, PhD
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
- Department of Pathology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
Nicholas Allan Buckley, MD, FRACP
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
- The POW Clinical School, University of New South Wales, Sydney, Australia
Andrew Hamilton Dawson, FRACP, FRCP
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
- School of Population Health, University of Newcastle, Newcastle, Australia

Received 30 March 2009 ,Revised 9 June 2009 ,Accepted 22 July 2009.

Amount of methemoglobin formed with increasing sodium nitrite concentration.

Amount of methemoglobin formed with increasing sodium nitrite concentration.
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Samples used to measure red, green, and blue values of methemoglobin. A drop (10 μL) of blood was placed on white absorbent material and scanned with a flatbed Canon Scan LiDE 25 scanner.

Samples used to measure red, green, and blue values of methemoglobin. A drop (10 μL) of blood was placed on white absorbent material and scanned with a flatbed Canon Scan LiDE 25 scanner.
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The variation of red, green, and blue color values with methemoglobin concentration (%) Scanned methemoglobin spots were analyzed with an Image J program to measure the mean color values.

The variation of red, green, and blue color values with methemoglobin concentration (%) Scanned methemoglobin spots were analyzed with an Image J program to measure the mean color values.
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The change in the color value of normal and 40% methemoglobin blood samples. The red color value of blood samples with hemoglobin levels from 9 g/dL to 17 g/dL was measured in an Image J program.

The change in the color value of normal and 40% methemoglobin blood samples. The red color value of blood samples with hemoglobin levels from 9 g/dL to 17 g/dL was measured in an Image J program.
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Color chart for the measurement of methemoglobin. The color chart was prepared according to the change in red, green, and blue value of blood samples with known methemoglobin concentration.

Color chart for the measurement of methemoglobin. The color chart was prepared according to the change in red, green, and blue value of blood samples with known methemoglobin concentration.
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Demonstration of the change in red, green, and blue value of blood samples with methylene blue, starting from a known concentration of methemoglobin A, before methylene blue addition, B, just after me

Demonstration of the change in red, green, and blue value of blood samples with methylene blue, starting from a known concentration of methemoglobin A, before methylene blue addition, B, just after methylene blue was added, C, after incubation with methylene blue for 1 hour.
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Bland-Altman plots of methemoglobin concentration estimated by spectrophotometric and color chart methods. The difference is plotted against the average of the two methods. Differences from the gold s

Bland-Altman plots of methemoglobin concentration estimated by spectrophotometric and color chart methods. The difference is plotted against the average of the two methods. Differences from the gold standard in future patient samples should lie between the limits 95% of the time.
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Please see page 185 for the Editor's Capsule Summary of this article.

Provide feedback on this article at the journal's Web site, www.annemergmed.com.

Supervising editor: Richard C. Dart, MD, PhD

Author contributions: FS wrote the first draft of the article, performed all laboratory analyses, analyzed the data, had access to all the data in the study, and had final responsibility for the decision to submit for publication. DMD and AHD designed and set up the study. NAB contributed ideas to design the study. NAB and AHD provided statistical advice on study design. All authors had a role in improving the study design and in reviewing and editing the final version of the article. FS takes responsibility for the paper as a whole.

Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. The authors have stated that no such relationships exist. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. This study was supported by the South Asian Clinical Toxicology Research Collaboration, which is funded by The Wellcome Trust/National Health and Medical Research Council International Collaborative Research Grant GR071669MA. The funding bodies had no role in analyzing or interpreting the data or writing the article.

Publication date: Available online October 8, 2009.

Reprints not available from the authors.

PII: S0196-0644(09)01281-5

doi: 10.1016/j.annemergmed.2009.07.022

« Previous Next » Annals of Emergency Medicine
Volume 55, Issue 2 , Pages 184-189 , February 2010