Common Tests for CU Patients

ANA (antinuclear antibody panel)—This can be altered in rheumatoid arthritis, lupus, collagen vascular disease, inflammatory muscle disease, and liver disease. ANA looks for specific autoimmune diseases: lupus, Sjogren’s syndrome, scleroderma, Raynaud’s, mixed connective tissue disease, rheumatoid arthritis, primary biliary cirrhosis, thyroiditis, and chronic active hepatitis. Some of these diseases (notably lupus) can not show up in testing for years, even though you have the disease. Also, results will depend on how active the disease currently is.

Autologous serum skin test (ASST)—This test is still not widely available, so it may take some hunting around to find a local clinic or hospital that offers the test. The ASST involves taking a sample of your blood, spinning it down in a centrifuge to separate the serum, and the serum is then injected back into your arm. A wheal/flare response is considered positive for autoimmune CU.

Basophil histamine release test—This blood test, an alternative to the ASST, is used to confirm positive results of ASST.

Bone Marrow Biopsy—In suspected mastocytosis, the medical community considers a bone marrow biopsy the ‘gold standard’ test. A sample is usually taken from the long bones of the legs. The sample should be taken at three different spots and should be taken by a person and a hospital trained in doing masto biopsies. Remember, you can get a false negative with this test. It is believed that mast cells cluster together (usually at the ends of the bones) and the person taking the sample might not hit the right spot where they are presently clustering.

CBC (Complete Blood Count)—This test looks at general health and blood cell counts and can rule in and out some glaring things such as lymphoma, which has been associated with cold urticaria.

Chem 20—This is an extension of the CBC, but just goes a little deeper into the general health of an individual.

Complement—A group of proteins in the blood that help fight off infections. (Low complement levels are associated with immune and autoimmune conditions)

  • C1 esterase—Another complement test which evaluates for much of the same thing as the CH50. Sometimes the CH50 is more sensitive.
  • CH50—This test looks at “complement activity”. Sometimes complement proteins are active in various types of Lupus, Rheumatoid Arthritis (RA) or other things like hepatitis, hereditary angioedema, ulcerative colitis, some kidney issues, etc.

Creatinine—A blood test that measures kidney function. Often measured concurrently with BUN (blood urea nitrogen)—both are waste products. Raised levels of creatinine kinase are seen following heart attack, stroke, alcoholism, electric shock etc as well as steroid use. Elevated creatinine and BUN can signal kidney disease, since itching (without hives) is a symptom of kidney failure.

Cryofibrinogen assay—This test is to determine the presence of cryofibrinogen, an abnormal protein in the blood plasma, as is sometimes the case in people with cold urticaria. Cryofibrinogenemia can be a primary condition or it may arise in association with an underlying condition.

Cryoglobulins—Abnormal protein complexes that show up in some diseases: multiple myeloma, leukemia, macroglobulinemia, connective tissue disease (like lupus), mononucleosis, hepatitis, endocarditis, lymphoma and other malignancies, and glomerulonephritis. A test for cryoglobulins crosses a lot of the same ground as the C1 esterase and the CH50 and may be redundant

ESR (erythrocyte sedimentation rate)—Measures the distance that red blood cells settle in a tube (or how quickly they fall to the bottom), which can be associated with any of the conditions already mentioned as well as a host of other things. When swelling and inflammation are present, the blood’s proteins cause blood cells to clump together more rapidly than normal. Generally, the faster the blood cells fall, the more severe the inflammation. It’s not unusual to see ESR elevated in chronic urticaria, especially urticarial vasculitis.

Flow cytometry of the bone marrow aspirate can detect mast cells in the bone marrow, and apparently this is much more sensitive than a bone marrow biopsy. With this method, doctors can detect abnormal mast cells in the bone marrow of patients with adult-onset indolent mastocytosis even if they have a normal-appearing bone marrow biopsy and tryptase levels of less than 20 ng/ml.

Haematocrit—This measures the number of red blood cells present in a sample of blood. Low levels (anaemia) are common in people with chronic diseases.

24-hour histamine urine test—This test measures histamine levels in urine. For diagnosing mastocytosis, the 24 hour N-Methyl Histamine urine test is preferred.

Liver Function—These tests are looking at the possibility of hepatitis.

MRI (Magnetic Resonance Imaging)—Use of powerful magnetic coils to generate pictures of the body by visualising cells, fluid and minerals within the organs.

RF (Rheumatoid Factor)—An antibody which is present sometimes in RA, Lupus, Hepatitis, chronic viral infection, mononucleosis, scleroderma, and others.

Skin Biopsy—Used to help diagnose urticarial vasculitis and urticaria pigmentosa. After these types of biopsies, you will need to have a couple of stitches put in to sew up the area where the skin has been cut out. The stitches will stay in for about a week. There are 3 main types of biopsy:

  • Shave biopsy—A shave biopsy means shaving off the top layer of skin under local anaesthetic.
  • Punch biopsy—A punch biopsy involves removing a deeper tissue sample. A small circle of full-thickness skin is removed.
  • Incisional or excisional biopsy—Incisional biopsy means using a surgical knife to remove a small piece of the suspicious area. A piece of full-thickness skin is removed. Excisional biopsy is the same, but the whole of the suspicious area is removed.

T3 and T4—These tests look at thyroid involvement, either hyperthyroid or hypothyroid.

  • TSH (thyroid stimulating hormone)—This test is looking for thyroid involvement and is often done in conjunction with T3 and T4.
  • Urinalysis—Testing of a urine sample for protein, red blood cells, white blood cells and formed elements. These are markers of abnormal filtering by the kidneys. A culture may also be done to check for infection.
  • White Blood Count (WBC)—Measures the number of white blood cells in the blood. Increased levels of white cells are one marker of inflammation, while decreased levels may indicate certain autoimmune diseases.
  • X-rays—A diagnostic test which uses electromagnetic energy to produce images of internal tissues, bones and organs on film.
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