# The Impact of a Laboratory Error on a Patient’s Well Being: A Case Report on Overdiagnosis and Its Consequent Iatrogenesis

**Authors:** Luís Laranjeira Correia, Joana Ferreira Vieira, Catarina Oliveira Neves, Maria de Freitas Domingues

PMC · DOI: 10.7759/cureus.84446 · Cureus · 2025-05-20

## TL;DR

A lab error led to unnecessary cancer tests for a 77-year-old woman, causing emotional distress and highlighting the risks of overdiagnosis.

## Contribution

This case emphasizes the need for cautious test ordering and patient involvement to prevent iatrogenic harm and promote quaternary prevention.

## Key findings

- A laboratory error caused a urinary cytology test instead of a thyroid FNAC, leading to unwarranted cancer suspicion.
- The patient experienced anxiety and disrupted family life due to unnecessary invasive tests and follow-ups.
- The case underscores the importance of evidence-based test prescribing to avoid overdiagnosis and preserve healthcare resources.

## Abstract

Overdiagnosis, resulting from excessive use of diagnostic tests, can lead to unnecessary treatments and negatively impact patients' quality of life. This case highlights the importance of prescribing tests based on the best scientific evidence to avoid emotional and financial harm to patients while promoting quaternary prevention. A 77-year-old woman, undergoing surveillance for a thyroid nodule, mistakenly underwent a urinary cytology test, which revealed a suspicious finding. Due to this incidental result, the Family Physician referred her to a Urology consultation to rule out urothelial cancer. The subsequent investigations included renal and pelvic CT scans, urethrocystoscopy, and repeated urinary cytology, all of which yielded negative results for malignancy. Throughout this process, the patient experienced anxiety, sadness, and loss of appetite, which also affected her family life.

The test requested by the Family Physician was a non-cervicovaginal exfoliative cytology, which can encompass various types of cytology. However, due to a laboratory error, urinary cytology was performed instead of a fine-needle aspiration cytology (FNAC) of the thyroid. This mistake led to an unfounded suspicion of cancer, causing significant anxiety for the patient and her family. The cascade of invasive tests and the use of limited healthcare resources underscore the dangers of overdiagnosis and the challenge of maintaining healthcare system sustainability. This case illustrates the importance of quaternary prevention, encouraging a cautious approach to ordering diagnostic and therapeutic tests, as well as involving patients in informed decision-making regarding their health. The role of the Family Physician is crucial in understanding patients' concerns and needs, promoting a holistic, patient-centered approach to healthcare delivery.

## Full-text entities

- **Diseases:** cancer (MESH:D009369), anxiety (MESH:D001007), loss of appetite (MESH:D001068), thyroid nodule (MESH:D016606), urothelial cancer (MESH:D014523)
- **Species:** Homo sapiens (human, species) [taxon 9606]

## Full text

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## Figures

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## References

4 references — full list in the complete paper: https://tomesphere.com/paper/PMC12177551/full.md

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Source: https://tomesphere.com/paper/PMC12177551