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‘.)
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.
Sarah goes to the phlebotomy clinic at one of two hospitals near to where she lives where she can have a blood sample taken while she waits and more quickly than waiting for an appointment at the GP surgery.
Tony finds it convenient to have his blood samples taken at a phlebotomy clinic in his local ASDA store when he happens to be passing it; he doesn’t need an appointment and never waits long.
For some types of blood tests people will be asked to fast (not eat) 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.
Gordon doesn’t like having to fast before some of his blood tests because he enjoys having his breakfast and cup of tea first thing in the morning and can’t always get an appointment as early as he would like.
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.
Joanne has got into a routine of having regular blood tests for her lithium, thyroid and kidney function levels and doesn’t mind it at all.
Peter starts to sweat if it takes more than one attempt to get blood out of him; he now asks the professionals to try harder to succeed at the first attempt. When used a lot, his veins collapse or roll away from the needle.
Tina’s veins tend to collapse and she finds that butterfly needles are more effective at getting blood out of her than the larger size needles but she has been told these are more expensive.
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.
Margaret explains that because the bottles provided for urine specimens have such a narrow neck she first urinates into an old beaker and then transfers it into the small bottle.
Jill was surprised to be asked to provide a urine sample recently. She was told it was to look for protein, but she wasn’t told why.
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.
Gerald says that when his blood pressure is measured by his GP it is normal but when measured by a stranger it is usually high.
Jim B regularly uses a home blood pressure monitor and finds that whenever he has it measured at the GP surgery or the renal clinic the figures are higher because he is less relaxed.
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.