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FDA Recommends Pooled of Blood Testing for Zika Virus

by | Aug 1, 2018 | Diagnostic Testing and Emerging Technologies, Testing Trends-dtet

The U.S. Food and Drug Administration (FDA) revised recommendations for testing donated blood for Zika virus. The agency will now allow pooled testing of blood donations, rather than universal nucleic acid testing of individual units of blood. The agency said pooled testing is both more cost effective and "less burdensome" for blood establishments, but that […]

The U.S. Food and Drug Administration (FDA) revised recommendations for testing donated blood for Zika virus. The agency will now allow pooled testing of blood donations, rather than universal nucleic acid testing of individual units of blood.

The agency said pooled testing is both more cost effective and "less burdensome" for blood establishments, but that "when certain threshold conditions are present," such as an increased risk of local mosquito-borne transmission of Zika virus in a specific geographic are, a return to individual testing may be triggered.

The final guidance still requires blood establishments to test all donated whole blood and blood components for Zika virus using a nucleic acid test. Since 2016 two assays have been approved under investigational new drug applications—the cobas Zika (Roche Molecular Systems, Inc.) and the Procleix Zika Virus Assay (Grifols Diagnostic Solutions, Inc.). In May of this year, the FDA approved an additional claim for Roche's Cobas Zika test for pooled testing of blood or plasma donations.

U.S. Recommends Expansion of Newborn Screening
Health and Human Services Secretary Alex Azar approved the addition of spinal muscular atrophy to the list of conditions for which the U.S. government recommends newborn screening. Approximately 4 million infants are born and screened annually.

The secretary acknowledged that early screening and treatment can lead to decreased morbidity, including improved achievement of motor milestones. He cautions though, that the addition of spinal muscular atrophy is only a recommendation, not a requirement, and that he would like an update on outcomes, including any harms from screening, within two years.

This recommendation comes about 18 months after the FDA approved the first treatment for spinal muscular atrophy. While the drug is reported to be quite expensive ($750,000 for the first year of treatment and $350,000 after that), the addition of the condition to newborn screening is only expected to cost $1 to $5 per infant tested. Advocates say screening will likely detect 150 cases per year, which would otherwise not be identified until presenting with symptoms, at which point it may be too late to initiate treatment.

Focused Update on Less Common HER2 Testing Scenarios For Breast Cancer
The American Society of Clinical Oncology and the College of American Pathologists released a joint focused update of Human Epidermal Growth Factor Receptor 2 (HER2) clinical practice guidelines. Overall, current HER2 testing algorithms have been confirmed by recent clinical trials showing that for patients whose tumors lack gene amplification and are IHC 1+ or 2+, there is a lack of clinical benefit from adjuvant trastuzumab. This focused update provides additional guidance regarding less common HER2 testing scenarios, including in situ hybridization (ISH) equivocal cases.

The panel examined clinical data for three less common HER2 dual-probe ISH test result groups, assessed the most appropriate testing and interpretation algorithm, and eliminated the ISH equivocal category. The revised diagnostic approach for three less common groups includes more-rigorous interpretation criteria for dual-probe ISH testing and requires concomitant immunohistochemistry (IHC) review to ensure the most accurate HER2 status designation (positive or negative) based on the combined interpretation of the ISH and IHC assays. Additionally, the panel recommends:

  • Concomitant review be performed in the same institution to ensure comparable interpretation and assay quality.
  • There is insufficient evidence on analytical and clinical validity to endorse the use of multiple alternative chromosome 17 probe testing as the primary strategy to resolve uncommon HER2 test results by ISH.
  • Concomitant IHC review should become part of the interpretation of single-probe ISH results to allow the most accurate HER2 designation.

Childhood Cancer Survivors Should Be Screened for Endocrine Disorders
Lifelong surveillance for endocrine disorders is necessary for childhood cancer survivors, according to clinical practice guidelines released by the Endocrine Society. Childhood cancer survivors are at increased risk for endocrine disorders, with up to half of survivors developing an endocrine disorder during their lifetime.

Specific recommendations include lifelong periodic clinical assessment for growth hormone deficiency, life-long annual screening for thyroid- stimulating hormone deficiency, and lifelong annual screening for adrenocorticotropic hormone deficiency for those treated for tumors in the region of the hypothalamic–pituitary axis, especially those who received radiation. Diagnostic testing should use the same tests as used in the noncancer population, the society says.

American Cancer Society Lowers Age for Colon Cancer Screening
The American Cancer Society updated its colon cancer screening guidelines. The organization's most notable change was lowering the recommended age for routine colon cancer screening for patients at average risk from 50 to 45 years, an additional 22 million people. The society says a review of the literature by its experts showed that the rate of new cases of colorectal cancer occurring among younger adults is increasing. Radiation exposure to key endocrine organs (e.g., hypothalamus, pituitary, thyroid, and gonads) places cancer survivors at the highest risk of developing an endocrine abnormality over time, even decades after treatment.

The newly released guideline emphasizes individual preference and choice in testing options. Additional recommendations include:

  • Age: People who are in good health and with a life expectancy of more than 10 years should continue regular colorectal cancer screening through the age of 75. Screening for people ages 76 through 85 should be based on a person's preferences, life expectancy, overall health, and prior screening history, while people over 85 years of age should no longer get colorectal cancer screening.
  • Testing Type: The new guideline does not prioritize among screening test options. Recommended tests include: Annual screening with the fecal immunochemical test or the high sensitivity guaiac-based fecal occult blood test; the multi-target stool DNA test every 3 years; colonography every 5 years; and flexible sigmoidoscopy every 5 years; or colonoscopy every 10 years.
  • All positive results on non-colonoscopy screening tests should be followed up with timely colonoscopy.

Practice-Based Guidance for Laboratories Using Cardiac Troponin Assays
The Academy of the American Association for Clinical Chemistry released clinical laboratory practice recommendations for the use of cardiac troponin (cTn) in acute coronary syndrome. The recommendation was released in anticipation of additional of assay approvals and is intended to fill gaps in practice and improve consistency of implementation of cardiac biomarker assays.

The guidelines used expert opinion to provide guidance in 10 specific areas: quality control utilization, validation of the lower reportable analytical limits, units to be used in reporting measurable concentrations for patients and quality control materials (troponin is measured in nanograms per milliliter, it is recommended that the high-sensitivity assays be reported in nanograms per liter making reporting in whole numbers); 99th percentile sex-specific upper reference limits to define the reference interval; criteria to define high-sensitivity (hs-cTn) assays (detecting cTn at concentrations at or above the limit of detection in at least 50 percent of healthy men and women needed for hs-cTn assays); communication with clinicians and the laboratory's role in educating clinicians regarding the influence of preanalytic and analytic problems that can confound assay results; how to document preanalytical and analytical variables; harmonizing and standardizing assay results and the role of commutable materials; maintaining a 60 minute turnaround time to reporting of results from sample receipt and sample collection; and changes in hs-cTn concentrations over time and the role of both analytical and biological variabilities in interpreting results of serial blood collections.

First-ever Pharmacogenomic Guideline for Guiding Tamoxifen Therapy
There is sufficient evidence to use CYP2D6 genotype to guide decision-making for women who are being considered for tamoxifen treatment for early stage estrogen receptor positive breast cancer. The recommendation provides clinicians with information that will allow the interpretation of clinical CYP2D6 genotype tests, including dosing information and suggestions for use of an alternative hormonal therapy based on CYP2D6 genotype.

Breast Cancer Staging Uses Tumor Biology Markers
The eighth edition of the American Joint Committee on Cancer Breast Cancer Staging System was revised to incorporate tumor biology. It attempts to incorporate the fast-moving field of precision medicine in early breast cancer treatment protocols. Specifically, the staging system incorporates biologic tumor markers—estrogen receptor and human epidermal growth factor 2 status, and the 21-Gene Recurrence Score, that was prospectively validated in the TAILOR-X study. AJCC said that the changes in the staging system acknowledge the value of commercially available, gene-based assays and incorporated prognostic input alongside classification based on traditional anatomic factors.