Objective: To quantify the spatiotemporal factors and built environment effects on daily blood collection volumes at fixed sites using multi-source spatiotemporal data, explore the influence radii of different point of interest(POI) categories, and develop a classification framework for sites, thereby providing data references for efficiency diagnosis and network optimization of blood collection sites. Methods: We collected daily blood donation records from 16 fixed whole blood collection sites in Guangzhou in 2023, constructing a balanced “site-day” panel dataset (16 sites × 365 days = 5 840 observations). Multi-source geospatial data, including Amap POI, OpenStreetMap (OSM) road network, and meteorological data were integrated to establish 300 m, 500 m, 800 m, and 1 000 m buffer zones around each site. Variables extracted included counts of surrounding commercial facilities, distance to the nearest subway station, rainfall, and temperature. A two-way fixed effects panel model was employed with a first-order lag term of the dependent variable to capture the inertial effect of blood donation behavior. Based on the significant regression coefficients, a "Structure-Function Index (SFI)" was constructed for each site to identify its optimal buffer radius. Combining inherent site capacity (fixed effects) with the optimal SFI, a two-dimensional quadrant diagram was created to classify the sites. Results: The optimized model showed an adjusted R of 0.89 and a Durbin-Watson statistic of 1.90, with the lag term coefficient stable at 0.36 (P<0.05). Temporal effects were significant: campaign days increased blood collection by 1 717.75 mL, holidays by 3 755.53 mL, and overlapping holidays with campaign days by 5 650.49 mL (P<0.05). Rainy days reduced collection by approximately 419 mL (P<0.05), and each 1℃ rise in daily average temperature decreased collection by approximately 31 mL (P<0.05). Distance to the nearest subway station was significantly positive (coefficient 0.95-1.39, P<0.05). POI effects showed scale-dependent differences: within 300 m, leisure and entertainment (+173.65 mL/unit) and shopping (+2.95 mL/unit) were significantly positive; within 500 m, tourist attractions (+72.55 mL/unit) and hotels (+40.09 mL/unit) were significantly positive; within 1 000 m, these effects diminished. Based on the two-dimensional classification of inherent collection capacity and optimal SFI, sites were categorized into four types: core, potential, adjustment, and resource-dependent. Conclusion: This study elucidates the multidimensional determinants of blood collection site efficiency, and provides quantitative evidence for performance diagnosis. It proposes a "concentric-zone planning" approach for site selection assessment alongside a" station-specific strategy" classification framework, offering data-driven references for network planning and resource allocation in blood collection and supply institutions. It should be noted that blood donation site selection also involves complex factors such as budgetary constraints, interdepartmental coordination, and venue conditions. This study provides a spatial econometric perspective for the quantitative optimization of blood collection networks.

【Objective】 To detect the anti-SARS-CoV-2 antibody levels in blood donors in Guangzhou, so as to provide laboratory data support for the collection and clinical use of convalescent plasma. 【Methods】 Anti-SARS-CoV-2 antibodies were measured by ELISA in qualified donors. Among them, 326 donors who gave blood in February 2023 were tested for IgG antibodies, 444 donors were tested for neutralizing antibodies. In July 2023, 398 donors were tested for IgG and IgM. 【Results】 399 of 724 blood samples diluted with normal saline (1∶160) were IgG reactive, with a reactive rate of 55.11%. Chi-square test showed that there was a significant difference in the reactive rate of IgG among samples collected at different times (25.46% in February vs 79.40% in July, χ²=210.74, P<0.01, 95%CI: 7.97, 15.98), but there was no significant difference in the reactive rate between different genders and different age groups. IgM was detected in 5 of 398 blood samples, with a reactive rate of 1.26%. The IgG test results of these five blood donors were all reactive, whereas the nucleic acid test results were negative. Neutralizing antibody was detected in 440 of 444 blood samples, with a reactive rate of 99.10%, and 71.59% of the reactive donors had a neutralizing antibody level of 10 μg/mL or more. 【Conclusion】 Blood donors in Guangzhou have a high level of SARS-CoV-2 antibody, which is sufficient to provide convalescent plasma for clinical treatment.

The professional identity of medical postgraduates has great influence on their profes-sional learning, career development and realization of self-value. The effect factors of the professional iden-tity are as following:the conflict between personal needs and professional requirements, professional employ-ment prospect, the social recognition of medical profession and individuality. In this article, we suggest a feasible way to improve the professional identity for medical postgraduates by developing an interest in medical profession, optimizing specialty structure and improving personal comprehensive quality.