Clinical pathology selected abstracts

Editor: Deborah Sesok-Pizzini, MD, MBA, adjunct professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia.

Colonoscopic follow-up after abnormal colorectal cancer screening results

November 2025—Asymptomatic screening for colorectal cancer, the second leading cause of cancer-related death in the United States, can reduce incidences of the disease and mortality. However, even with the availability of multiple screening methods for colorectal cancer (CRC), it is estimated that more than one-third of people in the United States who are eligible for such screening are not up to date on their testing. Failure to get screened for CRC can be attributed to such factors as challenges with bowel preparation, lack of knowledge, fear of colonoscopy, lack of transportation, and lack of health insurance. Provider-based barriers include scheduling difficulties and long wait times for appointments. Blood-based CRC tests can be convenient, noninvasive options for improving compliance with screening guidelines. However, they are a two-step process in which patients with an abnormal result must undergo a follow-up colonoscopy (FU-CY). The amount of people who complete this second step is unknown. The authors conducted a study in which they analyzed closed claims data to determine the FU-CY rate after an abnormal blood-based test result and identified predictors of FU-CY using national data. The retrospective analysis focused on average-risk individuals, age 45, who received a commercial blood-based CRC screening test (Shield, Guardant Health) between May 2022 and September 2024 in primary care settings across the United States. The Shield test has 83 percent sensitivity for CRC and 90 percent specificity for advanced neoplasia. The authors linked anonymized data to aggregated administrative claims data from a deidentified database representing 320 million lives. They summarized the sociodemographic characteristics of the cohort, determined the FU-CY rate within six months of an abnormal result, and used multivariable logistic regression to identify predictors of FU-CY within six months. Of the 6,068 people who met study inclusion criteria, 452 (7.4 percent) had an abnormal result, and 228 (50.4 percent) of the latter had at least six months of follow-up. A total of 111 (49 percent) patients received FU-CY within six months, and mean time to FU-CY was 66.4 (standard deviation [SD], 46.3) days. Overall, 128 (56 percent) people received a FU-CY at any time, with a mean time to FU-CY of 98.3 (SD, 101.4) days. The FU-CY rate was higher among people with at least 12 months of follow-up. Of interest, adjusted analysis showed that people with Medicare Advantage were less likely to undergo FU-CY within six months compared with those who had private insurance. In addition, having fewer comorbidities was associated with FU-CY at six months. The rate of people completing colonoscopy within six months (49 percent) was similar to follow-up after stool-based screening in other recent studies. The authors’ findings suggest that blood-based CRC screening and stool-based screening have similar rates of patient adherence to FU-CY. The authors concluded that this study shows that age, race, and ethnicity were not significant predictors of FU-CY. They also noted that as blood-based CRC screening technologies evolve, it is necessary to prioritize strategies to ensure timely FU-CY, similar to what is needed for stool-based screening tests.

Zaki TA, Zhang NJ, Forbes SP, et al. Colonoscopic follow-up after abnormal blood-based colorectal cancer screening results. Gastroenterology. 2025. doi.org/10.1053/j.gastro.2025.07.019

Correspondence: Dr. Folasade P. May at [email protected]

Red cell transfusion in acute myocardial infarction

Transfusion guidelines provide evidence-based practice recommendations for many critical and chronic medical conditions requiring blood transfusion. Threshold-driven indications for red blood cell transfusion based on hemoglobin level are common. International guidelines from the Association for the Advancement of Blood and Biotherapies (AABB) focused on the evaluation of data from randomized clinical control trials that compared liberal versus restrictive transfusion strategies. The general recommendations are for more restrictive transfusion strategies, which use a hemoglobin threshold of less than 7 g/dL. Restrictive transfusion strategies are intended to minimize and mitigate the risks of unnecessary transfusions and help prevent blood shortages. However, because the prevalence of acute and chronic illnesses varies by population, different transfusion strategies may be necessary. More than 3 million cases of acute myocardial infarction (AMI) occur in the United States each year and lead to 1 million deaths. Rates of recurrent AMI can reach 2.5 percent at 90 days, and rates of anemia in elderly AMI patients may be as high as 40 percent. The authors, who are members of the AABB International Clinical Practice Guidelines Panel, reviewed the current literature and examined RBC thresholds in patients with AMI to develop a guideline that provides recommendations for RBC transfusion in such patients. Their efforts were timely, as they followed the publication of data from two large randomized controlled trials, MINT (Myocardial Ischemia and Transfusion) and REALITY (Restrictive and Liberal Transfusion Strategies in Patients with AMI), which were similarly designed to test two different hemoglobin thresholds. These trials reported different results for key outcomes. To update AMI transfusion guidelines, the authors performed a meta-analysis of eligible trials using Cochrane methods. They used GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methods to summarize evidence and develop recommendations. The guidelines primarily focused on the patient’s perspective relative to the medical, financial, and psychological effects of transfusion for AMI, with a secondary focus on health care system issues, such as conservation of the blood supply. Based on their analysis and review, the authors recommend a liberal RBC transfusion strategy when the hemoglobin concentration is less than 10 g/dL (conditional recommendation, low certainty of evidence) for hospitalized patients with AMI. The concern is that a restrictive strategy of 7 to 8 g/dL may increase mortality for patients with AMI. However, the authors emphasized that clinicians should adopt mitigation strategies to reduce potential adverse events associated with more liberal strategies and that hemoglobin values alone should not determine the decision to transfuse. They noted that additional research questions should address the balance between risks and benefits of transfusion in subpopulations of patients with AMI.

Pagano MB, Stanworth SJ, Dennis J, et al. Red cell transfusion in acute myocardial infarction: AABB international clinical practice guidelines. Ann Intern Med. 2025. doi.org/10.7326/annals-25-00706

Correspondence: Dr. Monica B. Pagano at [email protected] or Dr. Simon J. Stanworth at [email protected]