Published in PLOS One on 2026-08-04, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Christine Prosperi, Natalya Kostandova, Andrea C Carcelen, Kalumbu H Matakala, Innocent C Bwalya, Gloria Musukwa, Mutinta Hamahuwa, Irene Mutale, Kenny Situtu, Gershom Chongwe, Phillimon Ndubani, Edgar Simulundu, George Chipulu, Joseph Musowoya, Jonathan Kaunda Mwansa, Vickins Malambo, Moses Chakopo, Chaambwa Hachoose, Miriam Kabalo, Emmanuel Luwaya, Auto Madzire, Rebecca Moyo, Clement Chimuka Mukwengo, Tula C Mwansa, Sandwe Nkoma, Brian Siwakwi, Chipo Syamungulu, Susan Nafukwe, Evans Betha, Lombe Kampamba, Kelvin Kapungu, Japhet Matoba, Passwell Munachoonga, Mathias Muleka, Webster Mufwambi, Sydney Vwalika, Alvira Z Hasan, Amy K Winter, Constance Sakala, Francis Dien Mwansa, William J Moss, Simon Mutembo, Pierre Roques
Source: PLOS One • DOI 10.1371/journal.pone.0341389
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Residual blood specimens collected at health care facilities provide a low-cost and readily available specimen source to monitor population immunity through serological surveillance compared to more resource-intensive probability-based surveys. Despite concerns about the representativeness of these specimens, there has recently been increased interest in the use of residual specimens, driven by the need for rapid estimates of seroprevalence during outbreaks to inform response and prevention. Although residual specimen collection is a key component of surveillance systems in some settings, there is limited evidence of its implementation in low- and middle-income countries. We conducted a pilot project at three health facilities in two districts in Zambia between September 2021 through July 2022 to demonstrate the feasibility of residual blood specimen collection integrated into the health system to estimate measles seroprevalence. Through this pilot project, we were able to collect residual pediatric and adult specimens but with some modifications needed if residual specimen collection were to be implemented at scale, such as better integration into the routine functioning of laboratories and health facilities. This paper summarizes our experiences designing and implementing this residual blood specimen collection, including the lessons learned and recommendations for collecting residual specimens from hospitals.
Introduction
Serological surveillance is the use of blood specimens to test for antibodies such as those that signal exposure or immunity to pathogens of interest. This information can be linked to sociodemographic characteristics and epidemiological data to estimate the burden of disease, identify risk factors for exposure, monitor trends in disease, as well as identify population immunity gaps to vaccine-preventable diseases by age and location [1,2]. The gold standard study design to estimate population-level seroprevalence is a high-quality serological survey that uses probability-based sampling. However, this design requires substantial financial, personnel, transportation, and other resources [2–4]. A nationally representative serological survey provides valuable information to develop population immunity estimates at subnational levels, but in many settings they are conducted infrequently (e.g., every four or five years) due to the extensive resource requirements and are specific to a limited number of priority diseases [5–7].
Residual blood specimens collected at health care facilities comprise leftover blood, plasma or serum after clinical testing. These specimens are typically discarded but could provide a low cost, readily available specimen source to monitor population immunity through serological surveillance. The use of residual specimens at health facilities can leverage existing infrastructure because the laboratory equipment and personnel exist and the blood specimens collected for other purposes. Many countries have used residual specimens to monitor seroprevalence to a variety of pathogens, particularly for emerging or reemerging pathogens during an outbreak [8–10]. However, there are concerns that epidemiological inferences from residual specimens may be limited because they represent only healthcare-seeking populations [11], and collecting specimens from clinics for patients with specific medical conditions may increase the risk of biases if associated with the disease of interest. Accounting for differences between the patient population attending the health facility and the general population may help improve generalizability.
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider research & evidence desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2026 Christine Prosperi, Natalya Kostandova, Andrea C Carcelen, Kalumbu H Matakala, Innocent C Bwalya, Gloria Musukwa, Mutinta Hamahuwa, Irene Mutale, Kenny Situtu, Gershom Chongwe, Phillimon Ndubani, Edgar Simulundu, George Chipulu, Joseph Musowoya, Jonathan Kaunda Mwansa, Vickins Malambo, Moses Chakopo, Chaambwa Hachoose, Miriam Kabalo, Emmanuel Luwaya, Auto Madzire, Rebecca Moyo, Clement Chimuka Mukwengo, Tula C Mwansa, Sandwe Nkoma, Brian Siwakwi, Chipo Syamungulu, Susan Nafukwe, Evans Betha, Lombe Kampamba, Kelvin Kapungu, Japhet Matoba, Passwell Munachoonga, Mathias Muleka, Webster Mufwambi, Sydney Vwalika, Alvira Z Hasan, Amy K Winter, Constance Sakala, Francis Dien Mwansa, William J Moss, Simon Mutembo, Pierre Roques. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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