Fasting Duration and Differences Across Routine Laboratory Tests

Abstract
Importance Fasting before blood collection is widely practiced to reduce preanalytical variability, yet whether fasting-related differences are clinically meaningful across a broad panel of routine analytes has not been systematically evaluated using clinical data.

Objective To evaluate whether fasting duration is associated with routine laboratory test results and whether observed differences exceed established analytical performance specifications (APS).

Design, Setting, and Participants Retrospective single-center cross-sectional study using laboratory information system data collected between February 2021 and December 2023 from a single 670-bed secondary-care university hospital in the Seoul metropolitan area, Republic of Korea. All samples were drawn from outpatients at the institution’s central phlebotomy unit. Participants were adult outpatients (≥18 years) with documented fasting duration. Data were analyzed from January 1, 2024, to July 24, 2026.

Exposure Fasting duration derived from the time elapsed between the patient’s last meal and blood collection, categorized as less than 8 hours, 8 to 12 hours, and more than 12 hours.

Main Outcomes and Measures Adjusted means across fasting groups were estimated using linear mixed-effects models with patient-level random intercepts, adjusting for age, sex, and department. Paired within-person analyses among repeatedly tested patients were performed to minimize between-patient confounding. Differences were compared with the European Federation of Clinical Chemistry and Laboratory Medicine biological variation–based total allowable error. Postprandial trends within the subgroup fasting less than 8 hours were assessed at 30-minute intervals.

Results The final dataset comprised 9 755 547 test results from 101 148 patients across 372 test items. Between-group comparisons identified APS-exceeding differences for 27 analytes. However, only 10 were confirmed in paired within-person analyses, suggesting confounding. Glucose (10.8%), triglycerides (20.1%), γ-glutamyl transferase (14.8%), and lipase (36.4%) were higher with less than 8 hours fasting. No analyte exceeded APS between the 8- to 12-hour and more than 12-hour groups. Within the less than 8-hour subgroup, glucose and lactate decreased significantly with increasing fasting duration, whereas lipid concentrations showed no significant linear trend.

Conclusions and Relevance This cross-sectional study found that fasting duration was associated with differences exceeding analytical performance specifications for only a few analytes, mainly glucose, triglycerides, γ-glutamyl transferase, and lipase. No estimable within-person difference between the 8- to 12-hour and more than 12-hour groups exceeded an available APS. These findings support analyte-specific rather than uniform fasting requirements.

Author/s:

Sunghwan Shin, Sollip Kim, Shinae Yu, Soo Jin Yoo, Kuenyoul Park, Jeonghyun Chang, Tae-Hyun Um, Chong Rae Cho, Dong Hee Whang

Projected Benefit of Bilateral Salpingo-Oophorectomy by Age in BRCA Carriers

Mary Cervantes — Mon, 28 Sep 2026 17:19:18 +0000

Date Added:

September 28, 2026

Journal/Publication:

JAMA Surgery

Publisher:

JAMA Network: JAMA Surgery

Publication Date:

September 23, 2026

URL:

Projected Benefit of Bilateral Salpingo-Oophorectomy by Age in BRCA Carriers

Type:

Clinical Research Results

Format:

Article

DOI (1):

doi: 10.1001/jamasurg.2026.4356

Keywords

Women's Health

Bilateral Salpingo-Oophorectomy

MeSH

Salpingo-oophorectomy

early detection of cancer

ovarian neoplasms

Decision Support Systems

Clinical

follow-up studies

Patients with BRCA mutations should consider prophylactic ovariectomies prior to age 50 based upon this epidemiological simulation. James W. Mold, MD, MPH

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Importance Women with a BRCA1 or BRCA2 variant face a high lifetime risk of ovarian cancer and are often advised to undergo preventive surgery (bilateral salpingo-oophorectomy [BSO]) before cancer develops. The recommended age of BSO is 35 years for BRCA1 carriers and is 45 years for BRCA2 carriers, but some women choose to delay surgery until the age of menopause; there is no standard upper age at which surgery is no longer advised.

Objective To estimate the residual lifetime risk of ovarian cancer among BRCA carriers by current age and projected age at BSO.

Design, Setting, and Participants This was a prospective cohort study in an international cohort of BRCA carriers monitored for incident ovarian cancer. A life table analysis used age-specific ovarian cancer incidence rates and competing mortality rates to estimate lifetime risk of ovarian cancer among women with a BRCA1 or BRCA2 pathogenic variant with both ovaries intact and no prior ovarian cancer at baseline. Patients were recruited between 1995 and 2024 across 24 international centers, and the mean (SD) follow-up was 4.4 (3.9) years.

Exposure Timing of BSO, defined as immediate BSO, delayed BSO, or no BSO.

Main Outcome and Measures Residual lifetime risk of ovarian cancer.

Results The cohort consisted of 4286 BRCA1 and 1427 BRCA2 carriers between the ages of 30 and 74 years at baseline (mean [SD] age, 42.0 [10.8] years). There were 249 incident ovarian cancers in the follow-up period. The lifetime risk of ovarian cancer was 55.0% (95% CI, 48.8-61.9) for a BRCA1 carrier and 24.1% (95% CI, 15.1-36.6) for a BRCA2 carrier. A 30-year-old BRCA1 carrier with BSO delayed to age 50 years had a projected residual ovarian cancer risk of 23.9% (95% CI, 20.7-27.4). At age 75 years, the residual risk of ovarian cancer was estimated to be 8.4% (95% CI, 1.7-22.7) for a BRCA1 carrier and 3.7% (95% CI, 0.1-22.7) for a BRCA2 carrier.

Conclusions and Relevance The residual risk of ovarian cancer for older women in good health is sufficiently high to consider preventive surgery. BRCA1 carriers who defer BSO until age 50 years may face a substantial risk of developing ovarian cancer.

Author/s:

Vasily Giannakeas, PhD, Adriana I. Apostol, MD, Claudia Diella, et al.