Testing Guidelines at a Glance

New Recommendations Simplify Testing for Chronic Kidney Disease

In late February, The National Kidney Foundation, the American Society for Clinical Pathology, and leading laboratories and clinical laboratory societies announced a new collaboration to improve testing for chronic kidney disease (CKD). Hypertension and diabetes put 75 million Americans at risk for CKD, but only one in three are aware they have the condition. The collaborative effort will improve screening, standardize the tests used to detect CKD, thus, increasing the comparability of test results between laboratories, and increase awareness and education around the condition to increase early recognition of the disease.

The new CKD Kidney Profile relies on evidence-based clinical practice guidelines to simplify ordering of the tests needed to detect and diagnose CKD by uniting them together under one heading on the laboratory requisition form or electronic health record order. It is hoped that streamlining of CKD test ordering for estimated glomerular filtration rate testing (serum creatinine with eGFR) and urine albumin-creatinine ratio (albumin, urine [e.g., microalbumin], quantitative).

Additionally, the organizations recommend that

• Standardize albumin-creatinine ratio reporting using milligrams per gram to make comparison of results received from different laboratories easier.

• Laboratories use the same equation to estimate GFR

• Rename the microalbumin test to one that more accurately reflects what it is measuring—albumincreatinine ratio, urine.

Recommendations Guide Allele Selection for CYP2C19 Assays

The Association for Molecular Pathology (AMP) released consensus, evidence-based guidelines to aid clinical in the design of pharmacogenomic (PGx) assays. The recommendations are in response to recent studies that compared assays and found that no two assays examine the same alleles. AMP feels the need to standardize PGx allele function and phenotype nomenclature so that variations in test design do not negatively impact test interpretation or patient care.

The recommendations define the key attributes of PGx alleles recommended for clinical testing and identify a minimum set of variants (Tier 1) that should be included in clinical PGx genotyping assays. They also identify an extended panel of variant alleles (Tier 2).

Three Tier 1 CYP2C19 variant alleles were defined as those that are well-characterized and have been shown to have an effect on drug response. They have an appreciable minor allele frequency in a patient population, and have available reference materials. Nine Tier 2 variant CYP2C19 alleles are identified. These alleles meet at least one Tier 1 criteria, but not all criteria. They should be considered optional for inclusion in expanded clinical genotyping panels, as they are low frequency alleles, and do not currently have reference material available.

The organization said the CYP2C19 genotyping recommendations are the first of a series of recommendations for guiding pharmacogenomic testing.

Guidelines Released for Genetic Testing for Prostate Cancer

In response to the fact that there are no comprehensive guidelines regarding genetic counseling and genetic testing for prostate cancer (PCA) or optimal use and interpretation of commercially available, multi-gene panels, the Philadelphia Prostate Cancer Consensus 2017 convened with the goal of developing a consensus-driven framework for comprehensive genetic evaluation of inherited PCA. The framework also addresses working framework for genetic counseling and management of inherited PCA in the multigene testing era.

Overall, the consensus statement outlines targeted testing for selected individuals, rather than population-based screening, in a manner consistent with strategies for testing BRCA1/2 for hereditary breast cancer. The expert opinion recommends:

• Patients should engage in shared decision making for genetic testing.

• Testing should include HOXB13 for suspected hereditary PCA, BRCA1/2 for suspected hereditary breast and ovarian cancer, and DNA mismatch repair genes for suspected Lynch syndrome.

• BRCA2 mutations should be factored into PCA screening discussions, as well as clinical management decisions.

• There was moderate agreement to test all men with metastatic castration-resistant PCA, regardless of family history, with stronger agreement to test BRCA1/2 and moderate agreement to test ATM to inform prognosis and targeted therapy.

• Genetic test results, particularly BRCA2 mutations, should be factored into prostate cancer antigen screening strategies.