THE VITAMIN B12 AND FOLATE PATHOLOGY INVESTIGATION
THE INVESTIGATION OF ERRORS IN PATHOLOGY TESTS
FOR VITAMIN B12 AND FOLATE DEFICIENCY
BY MEANS OF MEDICAL EXPERIMENTS
THE METHYLMALONIC ACID INVESTIGATION
MMA ERRORS
Summary
MMA Lab Errors
Laboratory Performance
Interpretation Errors

Index

This page contains the following sections:

You can go to a section by selecting the link.

Introduction

This investigation was performed to investigate very significant differences in serum total homocysteine results reported by several laboratories during the The Serum B12 Experiment.

These are the laboratories:

  • NSW Biochemical Genetics Service at The Children's Hospital Westmead (CHW)
  • Mater Pathology (MP)
  • Queensland Health Pathology Service (QHPS)

Serum samples were collected on 39 sample dates, from 24 October 2005 to 27 November 2006.

Notes for Charts and Tables

Results are presented as charts and tables. You can view a larger chart in a new window by selecting the link shown above the chart. You can view the complete Excel table in a new window by selecting the link shown above the chart.

Most of the tables will initially appear at low resolution in the new window. To enlarge the table to full size, move the cursor from the white space below the table to inside the lower right corner of the table; an icon will then appear in the lower right corner of the table. Click on the icon to view the table full-size. Use the horizontal scroll-bar, in the new window, to view the entire table.

The chart and table numbers used here correspond to the sheet numbers in the Excel file, Series 1 - Serum B12 Investigation, which may be downloaded from Evidence.

These results can be verified from the scanned original pathology reports, which may be downloaded from Evidence.

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MP MMA Compared to CHW MMA

The important points to note, about MMA levels, from the MP Sample A and Westmead Sample Mean results are:

  • The maximum difference between the labs was 15.63 SD.
  • 14 results out of 22 were outside the 95% Confidence Interval.
  • 10 of those results were also outside the 99.0% Confidence Interval.
  • Eight of those results were also outside the 99.9% Confidence Interval.
Chart D13 Table B2

The important points to note, about MMA levels, from the MP Sample B and Westmead Sample Mean results are:

  • The maximum difference between the labs was 13.33 SD.
  • Seven results out of 11 were outside the 95% Confidence Interval.
  • All seven of those results were also outside the 99.0% Confidence Interval.
  • Six of those results were also outside the 99.9% Confidence Interval.
Chart D14 Table B2

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QHPS MMA Compared to CHW MMA

The important points to note, about MMA levels, from the QHPS Sample A and Westmead Sample Mean results are:

  • The maximum difference between the labs was 6.87 SD.
  • Eight results out of 15 were outside the 95% Confidence Interval.
  • Five of those results were also outside the 99.0% Confidence Interval.
  • Two of those results were also outside the 99.9% Confidence Interval.
Chart D16 Table B2

The important points to note, about MMA levels, from the QHPS Sample B and Westmead Sample Mean results are:

  • The maximum difference between the labs was 7.89 SD.
  • 15 results out of 19 were outside the 95% Confidence Interval.
  • 12 of those results were also outside the 99.0% Confidence Interval.
  • Nine of those results were also outside the 99.9% Confidence Interval.
Chart D17 Table B2

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Conclusion

Only two out of the four labs to measure my MMA, WCH and Westmead, gave results that could be correctly interpreted as indicating the existence of cellular vitamin B12 deficiency.

Both Mater Pathology and QHPS repeatedly gave very significantly different results for identical samples, when each lab was asked to test two samples of the same date. The results from Mater pathology and QHPS also failed to show the actual increasing trend in MMA levels, making any correct interpretation of cellular vitamin B12 status impossible.

The significant analytical errors were, in my opinion, caused by failure in quality control, not by method differences; the methods used by all four labs have been proven by other labs.

Having regard to the results of my investigation, set out in this web site, in my opinion, neither Mater Pathology nor QHPS MMA results are of sufficient accuracy and precision to be relied on for the diagnosis or monitoring of vitamin B12 deficiency.

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