TISSUE ARCHIVING


Henrietta Lacks’ story is a testament to the transformative power of tissue archives and the ethical responsibilities inherent in scientific discovery. Her legacy serves as a poignant reminder of the need for transparency, equity, and respect for patients’ rights


Colin also recounted an unusual but destructive incident that underscores the delicate nature of tissue storage: a species of small hover fly had laid its eggs within a hospital archive, and, as the eggs hatched, the maggots began to consume the wax encasing valuable tissue blocks. “The entire archive was badly infested,” Colin recalls, “and these tiny maggots were essentially destroying the samples by eating away at the wax, compromising years’ worth of valuable material.” This infestation not only damaged


irreplaceable tissue samples but also highlighted the unforeseen vulnerabilities in archive storage. Without strict temperature, humidity, and pest controls, even a small insect can wreak havoc on samples stored for critical research and diagnostic purposes. These pitfalls underscore the challenges that many healthcare facilities face with on-site tissue archiving, reinforcing the need for dedicated storage solutions that protect these critical materials and ensure their safe retrieval for future research and diagnostics.


Specimen retention: preservation, ethics, and practicality Specimen retention entails determining the appropriate duration for preserving and monitoring various specimens. Typically, specimens are not retained longer than necessary, but they serve invaluable purposes such as facilitating repeat or additional testing when required, validating new tests for public health investigations, and ensuring quality control measures are met.


In India, major institutions typically


retain slides and blocks for approximately a decade, while cancer referral centres extend this duration to 25 years. In the United States, the College of American Pathologists and the Joint Commission on Accreditation of Healthcare Organisations recommend retaining paraffin blocks, wet tissues, histology slides, and cytology smears for 10 years, with peripheral smears kept for seven days or until deemed appropriate for patient care.


In the UK, The Royal College of Pathologists and the Institute of Biomedical Science recommend retaining paraffin blocks for 30 years; if disposal is necessary before this timeframe, a representative block displaying the relevant pathology should be permanently kept. They also advise retaining slides and smears for at least a decade, and keeping wet tissues for about four weeks post-report delivery. There are advantages to longer retention times, tissue samples can be used again for research purposes and aid in the treatment of diseases. However, the ethical and legal implications of continued storage must be carefully reviewed, particularly when materials are no longer needed for clinical purposes but hold significance for teaching, quality assurance, audit, research, or other public benefit endeavours. Prioritising patient consent by ensuring they haven’t voiced objections during routine consent processes adds another layer of good practice. It’s also important to realise that there is approximately 8-10% growth year on year for the amount of paraffin blocks generated. Meaning in 10 years’ time the amount of paraffin blocks requiring storage could be doubled, this creates an impending issue when storage space options are limited. Storage conditions are of utmost importance, paraffin blocks and slides should be stored below 27°C or at room temperature, in humidity- controlled environments with proper pest management. Stained slides should be stored away from direct light to preserve the intensity and quality of stains over time. For unstained slides intended for future testing (such as molecular hybridisation, immunohistochemistry or


other speed-staining techniques) it is advisable to store them in completely dry conditions to ensure protein preservation and prevent hydrolysis.


In addition to slides and blocks, documentation, transfusion records, and paper reports may also require storage. When archiving these materials, it is crucial to maintain a safe and secure environment to prevent any compromise of the information and data they contain. Storage space, particularly in large built-up areas, comes at a premium and hospitals can often find themselves inundated with boxes of materials and no place to store them. Effective specimen storage is essential, particularly given the intricate and time-consuming nature of histopathology procedures. Pathologists understand the meticulous steps involved in achieving optimal results. Additionally, the process of extracting tissue samples, especially in biopsies, can be distressing for patients. Hence, the ability to store and retrieve tissue samples when needed is crucial. Currently, specimen storage methods


can be broadly categorised into two approaches: in-house archives and outsourced solutions. In-house archives typically belong to hospitals or institutions equipped with their own archival set- ups, while outsourced solutions involve standardised procedures implemented by external entities, encompassing meticulous documentation, equipment upkeep, and proficiency testing. The financial implications of maintaining an archive vary depending on factors such as laboratory size, specimen volume, conservation charges, and inventory management. These financial considerations span direct, indirect, opportunity, and future costs, necessitating a comprehensive approach to budgeting. Crucially, effective specimen archives must prioritise cost- effective handling, optimal storage conditions, waste disposal protocols, infection control measures, and thorough employee training.


The CellNass solution As issues with storage long plagued hospitals and laboratories, in 2003 a solution was formed. Nestled in mid- Wales in an unassuming business park is a large building, painted a rich


Without strict temperature, humidity, and pest controls, even a small insect can wreak havoc on samples stored for critical research and diagnostic purposes


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