By Joseph Zhou, Heidi Li, Ted Waszkuc, Upasana Abbot

Read full article, Nutritional Outlook, May 2002, 18-19 (PDF)

Summary prepared by Amy Kosowski

Most of us assume that the results of laboratory analysis are precise and accurate. In the supplement business, lack of accuracy in analysis can have a negative impact, not only on the consumer, but on the manufacturer and the supplement industry as well. In a recent article in Nutritional Outlook, Joseph Zhou, et al., of NOW Foods, provide a detailed explanation of how and why inaccurate test results come about.

According to Zhou, there are six main reasons that account for most inaccurate test results. The first is has to do with the analytical techniques themselves. Each method currently available has its own inherent flaws. Second, some labs use poor quality standards for comparison. Sometimes this is due to decomposition during long-term storage or may be a lack of good calibration procedures. The third problem is poor extracting of samples for analysis. The fourth common error is that the active ingredient in the sample can degrade during handling and analysis. Care must be taken to preserve samples. Human error is the fifth cause listed. Improperly trained personnel or differences between testers can effect the outcome of any analysis. Finally, there is some lack of agreement between manufacturers on which of the ingredients is the “active” one (or ones). Because plants contain hundreds or even thousands of compounds that give it its characteristic biological effect, it is difficult to come to a consensus on which of them should be measured.

All of these factors must be carefully considered when interpreting and accepting laboratory results. Ultimately, it is incumbent upon the manufacturer to make sure that their lab is accurate and reliable.