PNH Diagnosis & Symptoms


A PNH diagnosis is confirmed by a specialized blood test called flow cytometry. Usually, several other tests are performed during the diagnostic process to rule out complications of PNH and assess its severity. These may include a bone marrow biopsy, blood tests, x-rays, CT scans, an ultrasound and other specimen tests, i.e. urine. PNH can affect anyone of any age, but is most commonly diagnosed in young adults in their 20s or 30s. Usually, symptoms appear gradually so it can take years for a patient to be diagnosed.

Symptoms and severity of the disease vary widely, allowing some patients minimal disruption to their daily lives while others are severely limited in their ability to work, socialize and undertake simple physical activities such as light housework or walking.


Patients may experience few or many of these symptoms, as well as other less common symptoms. The progress of PNH cannot be predicted and when prescribing best possible treatment, your doctor should take into account your medical history, lifestyle and personal situation as well as the risks and benefits of each treatment.

  • haemolysis
  • anaemia
  • chronic severe fatigue
  • jaundice
  • nausea
  • abdominal pain
  • muscular pain
  • joint pain
  • dark/unusually coloured urine
  • lack of mental clarity
  • forgetfulness, difficulty concentrating
  • insomnia
  • tingling or numbness, particularly in the extremities
  • shortness of breath
  • headaches
  • dizziness
  • loss of appetite
  • esophageal (gullet) pain
  • erectile dysfunction
  • arrhythmia (irregular heartbeat)
  • difficulty dealing with daily tasks and situations
  • digestive problems
  • lack of motivation

Haemolysis triggers

Haemolysis usually occurs at a low to moderate level, at a rate at which a patient’s bone marrow can replace all or most of the destroyed cells, keeping the haemoglobin fairly stable, even if it is below normal levels. Sometimes heavier haemolysis occurs, resulting in more significant drops in haemoglobin and the red blood cells may need to be replaced via a blood transfusion. This is referred to as a haemolytic crisis and over time, patients will become familiar with what may trigger a crisis for them.  Any form of stress to the body may trigger haemolysis.

Some common stressors include:

  • bacterial or viral infections
  • exercise
  • lack of sleep
  • emotional upset
  • certain foods, usually those containing high levels of fat
  • alcohol
  • other illnesses, injuries or surgery
  • flying

Common complications

Chronic haemolysis places continuous strain on vital organs, particularly the liver; kidneys; and heart, thus increasing the risk of serious and life-threatening complications such as liver and/or kidney failure; heart attack; stroke; deep vein thrombosis; Budd-Chiari Syndrome (a clot or clots in the hepatic vein of the liver); or blood clots in other veins or organs.

Clots are the most common complication of PNH and the leading cause of death among patients. This is a scary thing for a patient to face, but knowing the signs and symptoms of a clot and getting treatment as soon as possible can minimize the risk of further complication. If you experience swelling in the limbs or abdomen and severe and/or sudden onset of pain, you should seek medical advice immediately.


PLEASE NOTE: This information is intended for general knowledge only and is not to be substituted for medical advice and its accuracy is not guaranteed. Please consult with your medical practitioner for further information regarding your personal circumstances.

This information has been prepared by PNHSAA Inc., is copyright protected and is used with their permission.