It looks like your daughter tested negative but so close to the borderline range that they wanted another test. When a child tests between 40 and 60 genetic testing is recommended.The following I found for you at this website: www.cindys-friends.comThe laboratory measures the concentration of chloride (and/or sodium). A positive test is one where the concentration of chloride (or sodium) is 60 milliequivalents per liter (mEq/L) or higher. Almost everyone with CF has values between 60 and 100 mEq/L. A negative test is one where the concentration of chloride (or sodium) is 40 mEq/L or lower. Very few people have values between 40 and 60 mEq/L. Once a test result is positive, it is always positive. Sweat test values do not change from positive to negative or negative to positive as a patient grows older, or when the patient has a cold or other temporary illness. There are no restrictions on activity or diet or special preparations before the test. However, one should not apply creams or lotions to the skin 24 hours before the test. All regular medications may be continued and will have no affect on the test results. Sweat test results are usually available to your physician the next working day after the test is performed. In a small number of cases, the quantity of sweat obtained is not sufficient to give an accurate result, and the test may need to be repeated. In a small number of cases, the sweat test results fall into the "gray zone" range, meaning not having CF and indicative of CF. In these situations, repeat sweat tests, as well as other diagnostic procedures, like genetic testing or measuring nasal PD, may need to be carried out. These can only be done after consultation with a physician.