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How will I know if PD is working well?

Most people, who have been on PD for a few weeks, start to feel quite well again. When you first start PD you may still be passing urine and this will help clear some waste and fluid from your body. Over the first two years on PD your urine output may decline, and your PD prescription may need to be changed. Symptoms such as feeling weak and tired, nausea and lack of appetite may be a sign that you are not receiving enough dialysis. A number of different blood and PD fluid tests can be carried out to assess how well your dialysis is working.

What tests will I need to check how well my PD is working?

People on PD need to have regular blood tests. Blood tests can tell how well PD is working, how well nourished you are, the state of your bones, how acid your blood is as well as your blood count, and iron level. The substances measured include:

Creatinine: This is the waste produced by muscles. A high creatinine level is not harmful, but it is an indicator of other waste in the blood. For an average sized person on PD the target level is below 800 mmols/l.

Potassium: This mineral is normally present in the blood. If the level gets too high or low it can cause the heart to stop. The normal level is 3.5- 5.0 mmols/l. Crisis levels are less than 2 or greater than 8, but most Kidney Units prefer you to have a large safety margin!

Urea: Urea is produced when the food we eat is broken down. The normal level is 3.3-6.6 mmols/l, but in dialysis patients a realistic target to aim for is a urea level of less than 25mmols/l. A high urea level will often cause sickness.

Phosphate: Phosphate is one of the substances in the blood necessary to keep bones healthy. The normal level is 0.8-1.4 mmols/l. The target level on dialysis is less than 1.8 mmols. A high level can cause itching and bone disease. Diet and phosphate binders can help to
control the level.

Glucose: The normal level of blood glucose is 3.0-7.8 mmols/l. For diabetics on PD the high glucose in the PD fluid (needed to remove fluid) can cause problems. If patients absorb a lot of glucose from the PD fluid they may put on body weight.

Bicarbonate: This is a measure of the ‘acidity’ of the blood. If the blood bicarbonate level is low, this means the blood is too acid, and can cause weakness and fatigue. The normal level of bicarbonate in the blood is 22-30 mmol/l. If the level is lower than normal, the
amount of PD may need to be increased to reduce the acid level in the blood, or a bicarbonate supplement may be needed.

Albumin: This is a type of protein, and is an indicator of how well nourished  a person is. The normal level is 35-50 grams/l. The target level is around 35 grams/l but this varies between Units, as Hospitals use different methods to measure albumin. 

Calcium: This mineral is needed to keep bones healthy. The normal level of calcium in the blood is 2.2-2.6 mmol/l.

Haemoglobin: Haemoglobin, or “Hb” as it is known, is the substance in the blood that carries oxygen around the body. The normal level is 11.5-15.5 g/dl in women, and 13-16.5 in men. A low Hb is called anaemia. The target level for people on PD is around 11-12g/dl. Iron supplements and EPO are common treatments for anaemia.

Ferritin: Iron is needed to produce red blood cells, and a guide to how much iron is in the body is to do a blood test for ferritin. The target level for ferritin in the blood is above 200 mg/l.

PFT: A Peritoneal Function Test. In some Units people are asked to collect all the PD fluid that they drain out, along with all the urine
they pass in a 24-hour period. The fluid is sampled, tested, and the amount of waste cleared by PD, and by the kidneys (if the person
passes urine) is then calculated. This is known as a Peritoneal Function Test (PFT) or ‘Adequacy Test’.

What are the signs/symptoms of PD not working well?

When people are not getting enough dialysis, they are sometimes referred to as under-dialysed. The main symptoms are tiredness, feeling weak, and going off food. However, these symptoms can also be due to other things such as:

  • Anaemia (a low blood count)
  • Stomach Ulcer
  • Constipation

A high level of urea in the blood can cause nausea and lack of appetite, leading to a loss of body weight or muscle size.

What will happen if my results show my PD is not working well?

A number of options can be considered to improve a person’s PD. These include:

Increasing the volume of the PD bags
Doing an extra exchange during the day, or at night with a machine.
Using special PD fluid such as Icodextrin.
Changing from CAPD to APD.
Increasing the time on APD, changing the number of exchanges, or the time each bag remains in the abdomen, or doing additional daytime exchanges.

But, sometimes changing the type of PD, the volume or number of bags used, will not be sufficient or be acceptable to the person, and the best option might be to change to Haemodialysis

More information about Peritoneal Dialysis click the links below

What is Peritoneal Dialysis?

Introduction to Peritoneal Dialysis

Are there different types of PD?

The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.