Katki H.A.,U.S. National Cancer Institute |
Li Y.,University of Texas at Arlington |
Edelstein D.W.,Carnegie Mellon University |
Castle P.E.,American Society for Clinical Pathology
Statistics in Medicine | Year: 2012
We focus on the efficient usage of specimen repositories for the evaluation of new diagnostic tests and for comparing new tests with existing tests. Typically, all pre-existing diagnostic tests will already have been conducted on all specimens. However, we propose retesting only a judicious subsample of the specimens by the new diagnostic test. Subsampling minimizes study costs and specimen consumption, yet estimates of agreement or diagnostic accuracy potentially retain adequate statistical efficiency. We introduce methods to estimate agreement statistics and conduct symmetry tests when the second test is conducted on only a subsample and no gold standard exists. The methods treat the subsample as a stratified two-phase sample and use inverse-probability weighting. Strata can be any information available on all specimens and can be used to oversample the most informative specimens. The verification bias framework applies if the test conducted on only the subsample is a gold standard. We also present inverse-probability-weighting-based estimators of diagnostic accuracy that take advantage of stratification. We present three examples demonstrating that adequate statistical efficiency can be achieved under subsampling while greatly reducing the number of specimens requiring retesting. Naively using standard estimators that ignore subsampling can lead to drastically misleading estimates. Through simulation, we assess the finite-sample properties of our estimators and consider other possible sampling designs for our examples that could have further improved statistical efficiency. To help promote subsampling designs, our R package CompareTests computes all of our agreement and diagnostic accuracy statistics. © 2011 John Wiley & Sons, Ltd.
News Article | November 14, 2016
NORTHFIELD, Ill. and CHICAGO and ALEXANDRIA, Va., Nov. 14, 2016 /PRNewswire-USNewswire/ -- The College of American Pathologists (CAP), the American Society for Clinical Pathology (ASCP), and the American Society of Clinical Oncology (ASCO) today released an evidence-based clinical...
Katki H.A.,U.S. National Institutes of Health |
Kinney W.K.,Kaiser Permanente |
Fetterman B.,Kaiser Permanente |
Lorey T.,Kaiser Permanente |
And 6 more authors.
The Lancet Oncology | Year: 2011
Background: Concurrent testing for human papillomavirus (HPV) and cervical cytology (co-testing) is an approved alternative to cytology alone in women aged 30 years and older. We aimed to assess the safety in routine clinical practice of 3-year screening intervals for women testing negative for HPV with normal cytology and to assess if co-testing can identify women at high risk of cervical cancer or cervical intraepithelial neoplasia grade 3 (CIN3) or worse over 5 years. Methods: We assessed the 5-year cumulative incidence, starting in 2003-05, of cervical cancer and CIN3 or worse for 331 818 women aged 30 years and older who enrolled in co-testing at Kaiser Permanente Northern California (Berkeley, CA, USA) and had adequate enrolment co-test results. Follow-up continued until Dec 31, 2009. We defined cumulative incidence to include prevalence at enrolment and incidence after enrolment. Prevalence at enrolment was defined as the ratio of women diagnosed with each outcome on the biopsy visit immediately after their enrolment screening visit to the total enrolled women. At screening visits only HPV test and Pap smear samples were collected, and at biopsy visits colposcopically directed biopsies were taken. To estimate post-enrolment incidence, we used Weibull survival models. Findings: In 315 061 women negative by HPV testing, the 5-year cumulative incidence of cancer was 3·8 per 100 000 women per year, slightly higher than for the 306 969 who were both negative by HPV and Pap testing (3·2 per 100 000), and half the cancer risk of the 319 177 who were negative by Pap testing (7·5 per 100 000). 313 465 (99·5%) women negative by HPV testing had either normal cytology or equivocal abnormalities. Abnormal cytology greatly increased cumulative incidence of CIN3 or worse over 5 years for the 16 757 positive by HPV testing (12·1% vs 5·9%; p<0·0001). By contrast, although statistically significant, abnormal cytology did not increase 5-year risk of CIN3 or worse for women negative by HPV testing to a substantial level (0·86% vs 0·16%; p=0·004). 12 208 (73%) of the women positive by HPV testing had no cytological abnormality, and these women had 258 (35%) of 747 CIN3 or worse, 25 (29%) of 87 cancers, and 17 (63%) of 27 adenocarcinomas. Interpretation: For women aged 30 years and older in routine clinical practice who are negative by co-testing (both HPV and cytology), 3-year screening intervals were safe because a single negative test for HPV was sufficient to reassure against cervical cancer over 5 years. Incorporating HPV testing with cytology also resulted in earlier identification of women at high risk of cervical cancer, especially adenocarcinoma. Testing for HPV without adjunctive cytology might be sufficiently sensitive for primary screening for cervical cancer. Funding: Intramural Research Program of the US National Cancer Institute/NIH/DHHS, and the American Cancer Society. © 2011 Elsevier Ltd.
News Article | March 2, 2017
ROCKVILLE, Md., March 2, 2017 /PRNewswire/ -- Kalorama Information thinks new guidelines will improve the market environment for certain molecular tests. Last month, the American Society for Clinical Pathology (ASCP), the College of American Pathologists (CAP), the Association for Molecula...
News Article | December 23, 2016
Each year, January is recognized as National Blood Donor Month. It falls just after the holidays, during which many of us find ourselves searching for the perfect gift for our loved ones – the one they’ll never forget – the one that comes from the heart. January celebrates those that have truly found the perfect gift – Blood Donors. Courtney Robinson, a member of the American Society for Clinical Pathology, has published an open letter calling for donations during National Blood Donor Month in January. “Blood donors give a part of themselves to another in need with no concern for race, gender, age or affiliation. It is amazing to know that people feel personal accountability to humanity and give the gift of life to another. In my opinion, there are few better ways to pay it forward,” Robinson writes. “I am a laboratorian, with deep roots in Blood Bank and I’m very passionate about blood donation,” she writes. “From within the medical laboratory, it is easy to see the constant, daily need for blood products. In the Blood Bank, the urgency is palpable. I have seen people from all walks of life be rescued from the very grips of death with these life-saving products. A new mom with a post-partum hemorrhage, a high school senior injured in a car wreck leaving prom, a grandparent in emergency need of Coumadin reversal, a premature infant struggling to thrive, a Sickle Cell patient in crisis, a child with leukemia – the list goes on and on. The need never goes away, it is always there.” For these individuals, donated blood products can be the gift of life. National Blood Donor Month has been observed in January since 1970. The goal is to increase blood and platelet donations during winter, typically one of the most difficult times to collect enough blood products to meet patient needs. Blood donation appointments can be made by downloading the American Red Cross Blood Donor App, visiting redcrossblood.org or calling 1-800-RED CROSS (1-800-733-2767) to make an appointment or to receive more information. All blood types are needed to ensure a reliable supply for patients. “People naturally love the feeling of giving because it lights up their spirit to show kindness to another. This innate trait is beautiful and humbling and makes you believe in the very purest of qualities of mankind – kindness,” says Robinson. “As author D. Elton Trueblood said it, ‘It takes a noble man to plant a seed for a tree that will someday give shade to people he may never meet.’ So dear blood donors – I thank you! Thank you for your noble, giving spirit, and for the most perfect gift of all!