1. Skin prick test for lactose intolerance: This test involves exposing the skin to lactose and observing for allergic reactions. While lactose intolerance is common, this specific test may be less frequently used than other methods like hydrogen breath tests.

2. Sweat test for cystic fibrosis: This test measures chloride levels in sweat to diagnose cystic fibrosis, a genetic disorder affecting the lungs and digestive system. While cystic fibrosis itself is relatively rare, the test is not commonly employed compared to other diagnostic methods.

3. Lumber puncture for neurodegenerative diseases: This procedure involves collecting cerebrospinal fluid (CSF) from the spinal canal to diagnose conditions like Alzheimer's disease or multiple sclerosis. While these diseases are concerning, lumbar punctures are generally reserved for specific indications due to their invasive nature.

4. Positron emission tomography (PET) scan for infections: PET scans use radioactive tracers to identify metabolic activity, often used in cancer diagnosis. While PET scans are gaining wider application, their use for diagnosing infections still holds less widespread adoption compared to other imaging techniques.

5. Genetic testing for rare diseases: With advancements in genetic testing, many rare diseases can be identified through this method. However, due to the sheer number of rare diseases and the ongoing development of genetic tests, specific tests for individual rare conditions may be uncommon.

6. Stool antigen test for giardia: This test detects giardia, a parasitic infection, by analyzing stool samples for antigens. While giardia is common, this specific test may be less frequently used than other diagnostic methods like microscopy.

7. Myocardial perfusion imaging for microvascular angina: This imaging technique uses radioactive tracers to assess blood flow in the heart muscle, potentially aiding in diagnosing microvascular angina. However, its use remains less common compared to other methods for diagnosing angina.

8. Bronchial thermoplasty for severe asthma: This minimally invasive procedure involves applying heat therapy to the airways to improve airflow in severe asthma cases. While it holds promise for specific patients, its application remains limited compared to other asthma management approaches.

9. Lung biopsy for interstitial lung disease: This procedure involves collecting lung tissue samples for diagnosis of interstitial lung disease (ILD). While ILD is a complex group of conditions, lung biopsies may be reserved for specific cases due to their invasive nature.

10. Electromyography (EMG) for nerve damage: This test measures electrical activity in muscles to assess nerve function. While EMG is valuable for diagnosing nerve damage, its application may be less common compared to other neurological assessments depending on the specific suspected issue.