Kidney health

Tests used to monitor kidney health

Repeated blood and urine tests at regular intervals are used to determine whether a person’s kidney performance is stable, improving or worsening, based on levels of creatinine in the blood and protein in the urine. (See also ‘Check-ups in general practice and hospital’.)

Blood tests

Many different chemicals can be measured in the blood. The people we spoke to commonly had other medical conditions alongside their kidney impairment and therefore had regular blood samples taken to monitor other things, such as the level of their blood sugar, cholesterol, thyroid hormones, liver enzymes, a drug called lithium (used for treating mental health conditions), their blood clotting time (INR) if taking warfarin, or blood cell counts, in addition to their kidney performance. (See also ‘Check-ups in general practice and hospital’).

Blood samples were most commonly taken at people’s local health centre by a nurse or phlebotomist (a specially trained healthcare assistant not usually qualified in nursing). Others went to a phlebotomy clinic at their local hospital or elsewhere.
For some types of blood tests people will be asked to fast for a few hours beforehand. Gordon and Xanthe didn’t like having to fast before a test because it could be difficult to get an early appointment and they didn’t like going without breakfast. Fasting isn’t necessary for blood tests that measure kidney function, but patients may be recommended to not eat meat in the twelve hours preceding a kidney blood test to ensure an accurate result.
It was common for people to say they didn’t mind having blood samples taken and it had become a part of their routine. However, others said they had difficulties with having blood tests either because they had a fear of needles or because their veins tended to collapse or roll away from the needle. Some said that their experience of having blood taken varied depending on the skill of the person taking the blood. Laura tells herself to let the blood flow once the needle is in.
Urine tests

Blood tests to check kidney function should be accompanied by a urine test for protein leakage from the kidneys. Although most people we spoke to recalled having occasional urine tests, few said they had been done regularly or with every blood test. Most people did not know why they were asked to supply a urine sample, although some people with diabetes suggested it was to test their sugar levels.
Blood pressure

One of the underlying causes of kidney impairment or chronic kidney disease is high blood pressure. People with kidney problems will therefore also have regular checks of their blood pressure and if necessary will be prescribed blood pressure lowering drugs and advised to adopt a healthier lifestyle. Several people said their blood pressure measurement would often be higher when measured by a doctor or in a stressful situation than it would be when they felt relaxed; this is a well-known phenomenon known as ‘White Coat Hypertension’ and it can make interpretation of the readings difficult. Xanthe said she preferred to have her blood pressure measured by the practice nurse rather than the GP for this reason. If blood pressure measurements are high in the clinic people may be invited to use a blood pressure measuring kit at home to obtain potentially more accurate readings. Several people said they used a home blood pressure monitor and John said he recorded his readings using a free app on his mobile phone.
Some general practices nowadays have an automated blood pressure measuring machine in the waiting area that patients can use but Flo had been advised that it would not give accurate readings in her case because she has an irregular heartbeat.

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