What is this summary about? This is a plain language summary of an article published in Alzheimer's & Dementia. It looks at a type of test called a lumbar puncture (also known as spinal tap) used in people suspected of having Alzheimer's disease or some other form of dementia. This summary focuses on how to do a lumbar puncture safely. Why is this important? Alzheimer's disease is a progressive condition, which means it gets worse over time. This leads to difficulties with thinking and memory. People with Alzheimer's disease show a build up of proteins called amyloid-beta and tau in the brain. This is followed by a gradual loss of brain cells and brain function. The changes in the brain are thought to occur years before symptoms appear. Lumbar puncture is a medical procedure during which samples of cerebrospinal fluid are collected. In Alzheimer's disease, it is used to examine cerebrospinal fluid biomarkers that can help diagnose disease. Lumbar puncture is traditionally considered as a painful and invasive procedure with frequent side effects. However, multiple studies indicate that a lumbar puncture can be performed safely. Side effects are typically mild and do not require specialist intervention. What are the key takeaways? Despite the low risk of serious complications associated with a lumbar puncture, physicians and their patients may be reluctant to recommend or undergo this procedure. Patient education, specialist training, as well as new methods concerning patient safety are important factors to support the widespread use of lumbar puncture in Alzheimer's disease.