A creatinine level of 1.4 is slightly above the normal range for men, which is 0.7 to 1.3 milligrams per deciliter, according to MedlinePlus. It's a bit higher for women because normal results fall between 0.6 and 1.1. This difference is due to men's typically greater muscle mass.
High creatinine levels are sometimes due to a blocked urinary tract, kidney conditions, dehydration, muscle-fiber breakdown or pregnancy problems, such as preeclampsia, states MedlinePlus. Muscular conditions such as myasthenia gravis and muscular dystrophy cause low levels, as well.
A creatinine test measures the amount of creatinine, a waste product of creatine, in the blood, MedlinePlus explains. Creatine helps provide energy to muscles. Kidneys dispose of creatinine in the urine, so abnormal levels indicate that these organs are malfunctioning. However, some medications, such as heavy-metal chemotherapy drugs and nonsteroidal anti-inflammatory drugs, interfere with the test. Therefore, patients are often instructed to put a hold on medications until after the test.
If kidneys have been damaged, they are not repairable, warns Mayo Clinic. Consequently, creatinine tests are often ordered for people with diabetes, kidney disease or high blood pressure. Kidney function also decreases naturally with age, WebMD says. However, most people do not experience serious problems until more than half their kidney function is impaired.