Quest Diagnostics Undertakes Patient Retest Program Due to Inaccurate Test Results

Starting in October, Quest Diagnostics Incorporated (NYSE:DGX) has quietly notified certain physicians and patients that it had reported “inaccurate” lab test results for Vitamin 25(OH) D. This ongoing campaign appears to be the largest voluntary patient recall/retest program known to have been instituted by a clinical laboratory company.The Dark Report and Dark Daily are first to report this remarkable story. Quest Diagnostics has told The Dark Report that, for a period of time in 2007 and extending into 2008, it reported inaccurate results for Vitamin 25(OH) D to some patients. The problem is related to Quest Diagnostics’ decision, several years ago, to switch away from immunoassay methods for Vitamin 25(OH) D testing and create a home brew assay that utilizes liquid chromatography-tandem mass spectrometry (LC-MS/MS).

To date, Quest Diagnostics’ voluntary program to alert physicians and patients to possibly inaccurate Vitamin 25(OH) D results seems most active in the Northeast. In particular, competing labs in the New York metropolitan area are reporting their belief that thousands of physicians have gotten letters from Quest Diagnostics informing them that certain of their patients had received unreliable results for Vitamin 25(OH) D tests performed during the period in question. Quest Diagnostics is offering a free retest to these patients, subject to the referring physicians’ authorization of the retest.

This rare campaign by Quest Diagnostics to alert physicians and patients and to offer free retesting is significant for a number of reasons. First, it is extraordinarily rare for any licensed, accredited laboratory in this country to acknowledge that, due to internal deficiencies in analytical processes, it reported unreliable test results on a sizeable number of patients over a specified period of time.

Second, Quest Diagnostics’ program to alert physicians and patients about the questionable Vitamin D test results and offer a free retest provides the entire laboratory industry with a management case study on how to respond to a laboratory discovers that significant numbers of patients and their physicians might have received unreliable test results that could negatively affect patient care.

Third, because the source of the unreliable Vitamin 25 (OH) D test results is a home brew assay, this episode could catch the attention of federal and state healthcare regulators. For example, the Food and Drug Administration (FDA) is known to want more authority to regulate laboratory-developed tests (LDTs), commonly called “home brew” tests.

Fourth, this recall/retest campaign has the potential to involve large numbers of physicians and patients. That is because the volume of Vitamin D testing tripled at Quest Diagnostics between May 2006 and May 2008, and Web sources report that Quest Diagnostics is doing as many as 500,000 Vitamin D tests each month. Accordingly, even a tiny percentage of the millions of Vitamin D home brew tests performed at Quest Diagnostics during this time could mean that tens of thousands of patients may be getting recall/retest letters from Quest Diagnostics. The number of patients and physicians affected by this episode may motivate federal and state healthcare regulators to take a closer look at what internal deficiencies created this problem at the nation’s largest lab company.

The current issue of The Dark Report provides detailed coverage of these events. This issue has been distributed to existing subscribing members. To see the individual intelligence briefings, use this link (or paste this URL in your browser: For more information on Charter Memberships go here.

Dark Daily asks that anyone with knowledge of this remarkable story about inaccurate Vitamin D results and willing to share insights can contact editor Robert L. Michel in complete confidence at or by dialing 512-264-7103.)

Additionally, Dark Daily would be interested in the opinions, advice, and questions that laboratory professionals have on this voluntary program of Vitamin D retesting. Because it provides a rare opportunity to learn how clinical laboratories and pathology groups should improve their own contingency plans, Dark Daily intends to provide ongoing news and intelligence about the full spectrum of issues triggered when a laboratory discovers it has reported inaccurate results to significant numbers of physicians and their patients.

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