dipstick

A dipstick is a tool used to determine the level of a liquid or to perform a chemical test on a liquid. The name derives from the action of dipping the instrument into the fluid and withdrawing it to observe results. Dipsticks come in various forms, including long metal or plastic rods for measuring liquid depth, and reagent-impregnated strips used to screen substances.

In automotive practice, the most common type measures engine oil level. A typical oil dipstick is a calibrated rod with a handle and an indicator marked with minimum and maximum levels. After a brief wait with the engine off, the dipstick is pulled, wiped, reinserted, and withdrawn to read the oil level and condition. Levels outside the marked range or a dirty/contaminated oil can indicate maintenance needs. Some vehicles use sealed engines without a dipstick, relying on electronic sensors instead.

In medicine, urine dipsticks are disposable strips coated with reagents that react with components in urine. Dipping the strip into a urine sample and comparing color changes to a chart yields semi-quantitative results for properties such as pH, glucose, proteins, nitrites, leukocytes, ketones, blood, and bilirubin. These tests are used for quick screening in clinics and home testing, but positive results require confirmatory laboratory testing.

Dipsticks are also used for other purposes, such as measuring liquid level in industrial tanks or testing substances in environmental or food analysis. Proper handling—keeping the sticks clean, reading within the specified time window, and following manufacturer instructions—assures accuracy and minimizes contamination.