Blood Tests
Routine blood tests for pulmonary hypertension patients
There are several blood tests that may be performed routinely on pulmonary arterial hypertension patients. While none of these tests specifically diagnose pulmonary hypertension they are very useful in managing the disease. Below are some of the routine blood tests performed.
LFTs: Liver Function Tests, used to monitor safety of certain pulmonary hypertension treatments. Liver function tests are used to screen for, detect, evaluate, and monitor for liver inflammation and damage. The panel includes ALT (Alanine aminotransferase), ALP (Alkaline phosphatase), AST (Apartate aminotransferase), bilirubin, albumin, and total protein. It is important to measure liver function for multiple reasons. The increased pressure in the pulmonary arteries leads to the right side of the heart not pumping efficiently, which leads to blood backing up in the body and hepatic (liver) congestion, which can cause damage to the organ. Some endothelin receptor antagonists (ERAs) have been shown to have a low risk of liver damage as well so it is important to check monthly liver function tests. The LFT panel offers more complete information on the liver and how well it is functioning than a CMP.
BMP: Basic Metabolic Panel, a common test for pulmonary hypertension patients. A BMP measures some basic electrolytes and basic kidney function and includes glucose, calcium, sodium, potassium, chloride, CO2 (carbon dioxide, bircarbonate), BUN (blood urea nitrogen), and creatinine. This test is important as many PAH patients are on diuretics, which can lead to wasting of important electrolytes or to renal damage if not monitored closely. This test is usually done at the first visit with the pulmonary hypertension expert and periodically over the course of treatment. It is a very useful test to perform after making changes to diuretic doses as it will allow the physician to see if the patient’s body is tolerating the medication.
TSH: Thyroid Stimulating Hormone blood test is used to evaluate for thyroid abnormalities in pulmonary hypertension patients.The TSH test is often the test of choice for evaluating thyroid function and/or symptoms of hyperthyroidism or hypothyroidism. There is thought to be an association between pulmonary arterial hypertension (PAH) and thyroid disease although it is not well understood. Most thyroid disorders are easily treated so it is important to diagnosis them with this blood test.
FBC: Full Blood Count/CBC: Complete Blood Count, commonly performed on pulmonary hypertension patientsThe complete blood count or CBC is a panel of tests that examines different parts of the blood and includes a white blood cell count (WBC), red blood cell count (RBC), hemoglobin, hematocrit, platelet count, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW). This test can help detect infection, anemia, and other specific hematological abnormalities. Since pulmonary hypertension patients are on different types of drugs that effect different levels in the CBC, this is an important test to monitor. Some endothelin receptor antagonists (ERAs) can lower a patient’s hematocrit, immunosupressants can lower the white blood cell count, and some prostacyclins lower platelet counts. This test is usually performed during or shortly after the first visit with a pulmonary hypertension expert and at routine intervals throughout treatment.
INR: International Normalised Ratio 
Prothrombin time test results can be presented in two ways:

  • Prothrombin time in seconds. Prothrombin time is usually measured in seconds — the time it takes for your blood to clot. This way of determining prothrombin time creates results that will vary depending on the laboratory and the method used to test the blood, but a sample range is approximately 10 to 14 seconds. A number higher than average means it takes blood longer than usual to clot. A lower number means blood clots more quickly than expected.
  • Prothrombin time as a ratio. For people taking the blood-thinning medication warfarin (Coumadin), results are given as a number that represents a ratio called the international normalized ratio (INR). The INR is a formula that adjusts for differences in the chemicals used in different laboratories so that test results can be comparable.

    An INR range of 2.0 to 3.0 is generally effective for people taking warfarin who need full anticoagulation, but may need to be slightly higher in certain situations. If your INR is higher than this range, that means your blood clots more slowly than desired. A lower INR means your blood clots more quickly than desired. The INR is used only for people on oral anticoagulant therapy. It's not useful in people whose PT is higher for other reasons.

What your results mean. Clotting too slowly. If your prothrombin time test reveals that your blood is clotting too slowly, this can be caused by:

  • Blood-thinning medications, such as warfarin (Coumadin), heparin
  • Liver problems
  • Inadequate levels of proteins (factors) that cause blood to clot
  • Vitamin K deficiency
  • Congenital factor deficiency
  • Presence of coagulation factor inhibitors

Clotting too fast. If your prothrombin time test reveals that your blood is clotting too fast, this can be caused by:

  • Supplements that contain vitamin K
  • High intake of foods that contain vitamin K, such as liver, broccoli, chickpeas, green tea, kale, turnip greens and products that contain soybeans
  • Estrogen-containing medications, such as birth control pills and hormone replacement therapy
How often do INR tests need to be done? When you first start taking warfarin you will need to have your INR tested frequently — maybe every 1 or 2 days for the first week — to work out your correct warfarin dose.

Once you’re stabilised on a warfarin dose that achieves your target INR, you won’t need to be tested so often. Many patients have the test once per month. From time to time you may need to have more tests — e.g. if you have any changes to your diet or medicines, as these may interact with the effect of warfarin in your body.

Because many factors can affect how warfarin works, it’s important to have your INR tests done when they are scheduled. This helps to make sure your INR stays within the target range. Talk to your doctor or pharmacist about any changes to your current medicines or diet — including when you are unwell or travelling — and before taking any new medicines, including those you buy over the counter from the pharmacy, supermarket or health food shop.
Warfarin interactions Many medicines can interfere with the way warfarin works, including prescription and non-prescription medicines, and complementary medicines such as vitamins and herbs. 

Watch our video, in which specialist Dr John Worthington explains why it is important to have more frequent INR tests if you start or stop taking any other medicine while you are taking warfarin.

Be medicine wise about warfarin interactions
  • Always tell your doctor, pharmacist and other healthcare providers that you are taking warfarin, especially before starting a new prescription, non-prescription or complementary medicine.
  • Always check with your doctor or pharmacist before making any changes to your current medicines.
  • Find out how your other medicines may interact with warfarin. Your doctor can make minor adjustments to your dose to manage many interactions.

  • For information on medicines interactions, you can ask your doctor or pharmacist, or read the consumer medicines information (CMI).
  • Keep a list of all the medicines you are taking — including any vitamins, herbal remedies and over-the-counter medicines — to show your healthcare providers, so they can check for any possible medicine interactions.
  • Have your INR blood test done whenever your doctor schedules this after you start or stop a medicine.
  • Wear a MedicAlert bracelet to show that you take warfarin.
The use of blood thinners in the treatment of pulmonary hypertension Blood thinners such as coumadin are commonly used to prevent or treat blood clots and are useful in the treatment of chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension as the narrowed pulmonary arteries are prone to blood clots. The risks and benefits of any medication should be discussed before placing a patient on therapy and this is very important before initiating blood thinners as there are serious risks associated with these medications. It is very important to perform regular blood tests (INRs) to measure how thin the blood is to avoid serious complications. If the blood is too thin (INR is too high) the patient is at risk for bleeding complications and if is too thick (INR is too low) they remain at risk of blood clots.
CMP: Complete Metabolic Panel, a useful test for pulmonary hypertension patientsThe CMP is a BMP plus albumin, total protein, ALP (alkaline phosphatase), ALT (alanine amino transferase) AST (aspartate amino transferase), and bilirubin. This test is used when the physician wants to measure basic electrolytes, renal function, and liver function. This test is useful in pulmonary hypertension for the same reason a BMP is, plus it has the added benefit of measuring liver function.

It is important to measure liver function for multiple reasons. The increased pressure in the pulmonary arteries leads to the right side of the heart not pumping efficiently, which leads to blood backing up in the body and hepatic (liver) congestion, which can cause damage to the organ. Some endothelin receptor antagonists (ERAs) have been shown to have a low risk of liver damage as well so it is important to check monthly liver function tests.
BNP: B-type Natriuretic Peptide in pulmonary hypertension patients a BNP is used to look for heart failure. If the levels are elevated in the blood, the heart is under strain and failing. This is useful in pulmonary hypertension patients as it may confirm that the pulmonary artery pressures, and therefore right heart failure, are being controlled by the current therapies a patient is on.  Or it may reveal that the right heart is stressed due to elevated pressures in the pulmonary arteries and excess fluid in the body. If the level is elevated, changes may be made to medications or additional tests such as an echocardiogram may be ordered.
Human Chorionic Gonadotropin is tested monthly for some PH patientsHCG is a blood pregnancy test. Two types of blood HCG can be ordered, a quantitative HCG and a qualitative HCG. The qualitative test gives a simple positive (pregnant) or negative (not pregnant) result. The quantitative test is more in depth and gives a numerical result that can estimates how far along a pregnancy is. Pulmonary hypertension patients in general should not become pregnant, as their hearts do very poorly with the increased blood volume associated in pregnancy. Certain drugs such endothelin receptor antagonists (ERAs) are known to be teratogenic (cause birth defects) so pregnancy must be avoided and monthly pregnancy tests are required while taking this class of medication. The HCG can also be measured in the urine.
Diet and Blood Thinners
Warfarin is a blood-thinning medication that helps treat and prevent blood clots. There is no specific warfarin diet. However, certain foods and beverages can make warfarin less effective in preventing blood clots. It's important to pay attention to what you eat while taking warfarin.

One nutrient that can lessen warfarin's effectiveness is vitamin K. It's important to be consistent in how much vitamin K you get daily. The adequate intake level of vitamin K for adult men is 120 micrograms (mcg). For adult women, it's 90 mcg. While eating small amounts of foods that are rich in vitamin K shouldn't cause a problem, avoid eating or drinking large amounts of:

  • Kale
  • Spinach
  • Brussels sprouts
  • Parsley
  • Collard greens
  • Mustard greens
  • Chard
  • Green tea
Certain drinks can increase the effect of warfarin, leading to bleeding problems. Avoid or drink only small amounts of these drinks when taking warfarin:

  • Cranberry juice
  • Alcohol
Talk to your doctor before making any major changes in your diet and before starting any over-the-counter medications, vitamins or herbal supplements. If you are unable to eat for several days or have ongoing stomach upset, diarrhea or fever, consult your doctor.

Diet and warfarin The cabbage family is high in vitamin K, and can affect your INR.

Certain foods and drinks can interact with warfarin and change the way it works. The most important thing is to be consistent in the types of foods and amounts you eat — don’t make drastic changes on a day-to-day basis. Get to know which foods can affect how warfarin works, so that you can eat consistent quantities of these each day.
  • If your diet changes (or you want to make changes to it), get advice from your doctor or pharmacist. You may need extra blood tests to check your INR.
  • Tobacco smoking can affect your International Normalised Ratio (INR). Quitting smoking has many benefits, but let your doctor know if you do quit, as you might need to have your INR checked.
  • Avoid crash diets or binge eating. This may affect your INR.
  • If you are sick and don’t feel like eating for a few days, this may affect your INR. Any new medicines that you may be taking when you are ill may also affect your INR. Let your doctor know if you are unwell or if you are taking any new medicines.
  • Limit alcohol intake.
Which medicines interact with warfarin?
Because so many medicines can affect warfarin, it is safer to assume that any medicine may affect warfarin, and get in the habit of checking with your health professional before making changes. Always check with your doctor or pharmacist before you start or stop taking any medicine.

Some medicines need to be avoided altogether, while other medicines may have a weaker interaction, or none at all. For some medicines that interact, you may still be able to take them, but you may need to have more frequent blood testing (INR monitoring) when you start (or stop) taking them. This enables you and your doctor to check if the medicine is interfering with your warfarin and to adjust the dose as needed.

Below are some examples of commonly used medicines that can interfere with warfarin, but it is not a complete list:

  • Some antibiotics
ciprofloxacin (e.g. Ciproxin), erythromycin (e.g. Eryc), metronidazole (e.g. Flagyl), sulfamethoxazole with trimethoprim (e.g. Bactrim)
  • Anti-inflammatory and pain reliever medicines, including those used to treat arthritis
aspirin (e.g. Solprin), meloxicam (e.g. Mobic), celecoxib (e.g. Celebrex), ibuprofen (e.g. Nurofen), indomethacin (e.g. Indocid), methyl salicylate (e.g. Deep Heat Cream), paracetamol (e.g. Panadol) – when used more often than usual
  • Some heart and cholesterol medicines
aspirin (e.g. Cartia), clopidogrel (e.g. Plavix), amiodarone (e.g. Cordarone), simvastatin (e.g. Zocor), fenofibrate (e.g. Lipidil)
  • Some ulcer and reflux medicines
esomeprazole (e.g. Nexium), cimetidine (e.g. Tagamet), omeprazole (e.g. Losec)
  • Some antidepressants
fluoxetine (e.g. Prozac), fluvoxamine (e.g. Luvox), paroxetine (e.g. Aropax)
  • Corticosteroids
prednisolone (e.g. Solone)
  • Thyroid hormones
Such as thyroxine (e.g. Oroxine)
  • Some anti-epileptic medicines
Carbamazepine (e.g. Tegretol)
  • Many cold and flu medicines
Some products contain medicines (e.g. paracetamol) which may interfere with warfarin
  • Some antifungals
Miconazole (e.g. Daktarin), fluconazole (e.g. Diflucan), griseofulvin (e.g. Grisovin)
  • Some vitamins, herbs and other complementary medicines
Such as vitamin K, vitamin E, fish oil, glucosamine, feverfew, garlic, ginkgo biloba, St John’s wort
These medicines may either increase the clotting risk or increase the bleeding risk of warfarin. Do not start or stop taking any medicine without speaking to your doctor or pharmacist.