UK National Kidney Federation - Peritoneal Dialysis

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. back to index
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! back to index
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 targetb to aim for is a urea level of less than 25mmols/l. A high urea level will often cause sickness. back to index
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. back to index
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. back to index
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. back to index
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. back to index
Calcium:	This mineral is needed to keep bones healthy. The normal level of calcium in the blood is 2.2-2.6 mmol/l. back to index
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. back to index
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. back to index
Peritoneal Function Test (PFT):	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. back to index

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.
back to index

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!
back to index

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 targetb to aim for is a urea level of less than 25mmols/l. A high urea level will often cause sickness.
back to index

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.

back to index

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.
back to index

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.
back to index

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.
back to index

Calcium:

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

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.

back to index

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.
back to index

Peritoneal Function Test (PFT):

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.

back to index

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:

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:

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.

NKF Controlled Document No. 247, How will I know if PD is working well?, written 26 January 2001. Last reviewed 19 October 2009.

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.

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