Test for psoriatic arthritis

Tests to Diagnose Psoriatic Arthritis

Blood Tests

These tests can help conform psoriatic arthritis and rule out other conditions, like rheumatoid arthritis.

  • Erythrocyte sedimentation rate (sed rate or ESR): Gives a rough idea of how much inflammation is in your body, which could be caused by psoriatic arthritis. But higher levels can come from other autoimmune diseases, an infection, a tumor, liver disease, or pregnancy, too.
  • Rheumatoid factor (RF) and anti-CCP antibody: These tests can rule out rheumatoid arthritis. People with that condition may have higher levels of these in their blood.
  • HLA-B27: More than half of people who have psoriatic arthritis with spine inflammation will have this genetic marker. You can get tested to find out if you do.
  • Iron tests: People with psoriatic arthritis may have mild anemia , or not enough healthy red blood cells.


These can show cartilage changes or bone and joint damage that suggests arthritis in your spine, hands, or feet. Psoriatic arthritis usually looks different on X-rays than rheumatoid arthritis does.

Bone Density Scan

Because psoriatic arthritis may lead to bone loss, your doctor may want to measure your bone strength. You could be at risk for osteoporosis and fractures.

Joint Fluid Test

A type of arthritis called gout can also cause joint pain. It happens when uric acid builds up in your system and creates crystals in your joint fluid. To rule it out, a doctor can use a needle to take a sample of fluid from one of your achy joints. If uric acid crystals are present, you have gout.

Diagnosing psoriatic arthritis can be complex. However everyone affected one or more of joint, tendon or spine inflammation. Most of the time patients have, or have had, psoriasis of the skin or nail. It can look different in each person: psoriasis may look different, some may get arthritis, and/or tendon involvement, and/or spine disease as well as possible eye disease or inflammatory bowel disease. As with any rheumatologic disease, we have a set of rules that we follow when we diagnose psoriatic arthritis; these are called criteria.

The criteria includes:

  • An examination by the physician determining if the joints are swollen or tender. The most commonly affected joints are the joints of the fingers and/or toes. The doctor will also look for inflammation in the tendons, spine, and swelling of fingers or toes known as “sausage digit”.
  • Blood tests to rule out rheumatoid arthritis called a rheumatoid factor and an Anti-cyclic citrullinated peptide antibody test. We would expect these to be negative in psoriatic arthritis. If either or both are positive we would consider the patient to have rheumatoid arthritis.
  • Sometimes an X-ray or radiograph of the hands or feet to look for any damage done. Psoriatic arthritis often has a type of damage not seen in other types of rheumatic disease. X-rays will also be useful in checking that there is no additional damage as you progress through treatment.
  • A skin examination to look for psoriasis. Some people may just have a patch of scalp psoriasis that never really bothers them that much. The arthritis is the biggest issue.
  • A nail examination. The nails will often have ridges and may be growing away from the nail bed.

Your rheumatologist will also take a full history of your symptoms and may perform additional examinations and bloodwork.

Psoriatic Arthritis Diagnosis

Psoriatic arthritis can be challenging to diagnose. Classic signs of the disease, such as pitted fingernails and swollen joints at the ends of fingers, are not always present. There is no one blood test used to diagnose psoriatic arthritis. It is a diagnosis of exclusion, which means physicians must rule out all other diseases that can produce similar symptoms, such as rheumatoid arthritis, reactive arthritis, and ankylosing spondylitis.

Diagnosis may require a medical history, physical examination, medical imaging, and lab testing.


Medical History

The physician will ask about the symptoms and when they began. He or she will also ask if any of the patient’s family members have experienced similar symptoms in the past. Patients are advised to report gastrointestinal issues and eye problems, as these may be related to psoriatic arthritis and other autoimmune diseases.

Physical Examination

The physician will examine the joints to look for tenderness, swelling, or stiffness. These are signs of inflammation and may indicate the presence of arthritis.

The physician will check the skin for signs of psoriasis, and may look at the scalp, navel, and groin, where psoriasis can sometimes go undetected. Fingernails and toenails will also be examined for signs of irregularities, such as nail pitting.

In This Article:

  • What Is Psoriatic Arthritis?
  • Psoriatic Arthritis Symptoms
  • Psoriatic Arthritis Causes
  • Psoriatic Arthritis Diagnosis
  • Psoriatic Arthritis Treatment

Medical Imaging

Several different types of medical imaging are used to look for signs of psoriatic arthritis, including inflammation and damage to joints.

  • X-rays can show irregularities involving bones. For example, they can show a loss of normal bone tissue (bone erosions) as well as abnormal bone growths, such as bone spurs (enthesophytes and osteophytes). X-rays can also show if the space between the bones of a joint is abnormally small. An abnormally small space is a sign of damage to cartilage and soft tissues. When psoriatic arthritis is in its early stages, x-rays may appear normal.
  • Ultrasound can show inflammation of the joints soft tissues. For example, the delicate tissue that surrounds a joint, called the synovium, is normally just a few cells thick. An ultrasound can show if the synovium has become thicker and inflamed, a condition called synovitis. Ultrasound can show other signs of inflammation, including an increase in normal blood flow, enthesophytes (bone spurs), and early signs of bone erosions. Ultrasound, particularly Doppler ultrasound, can detect joint changes in the early stages of psoriatic arthritis.
  • Magnetic resonance imaging (MRI) shows a more detailed picture than an x-ray, including the bone as well as surrounding soft tissue. In addition to changes to the bones, and MRI can show inflammation and other changes to soft tissues, including the joint’s entheses. MRIs are especially helpful in detecting sacroiliitis. In general, an MRI is more expensive and takes longer than an x-ray or ultrasound evaluation.

In addition to medical imaging, your physician may order lab tests.


Lab Tests

A doctor may order lab tests to help confirm or rule out the diagnosis of psoriatic arthritis. Common diagnostic lab tests include:

  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) tests measure inflammation in the body. Higher than normal inflammation can indicate psoriatic arthritis or another inflammatory disease.
  • Rheumatoid arthritis factor (RF factor) and citrullinated peptide (CCP) antibody tests can help rule out or confirm rheumatoid arthritis (RA). Rheumatoid arthritis is often confused for psoriatic arthritis and vice versa. If a lab test detects proteins called rheumatoid factor and/or citrullinated peptide antibodies, it indicates a possible diagnosis of rheumatoid arthritis.
  • Anti-nuclear antibodies (ANA) test identify ANA proteins, which can be found in the blood of people who have autoimmune disorders, including psoriatic arthritis.
  • Genetic testing can detect one or more genes associated with psoriatic arthritis. Gene testing may help support or rule out a diagnosis, though it is not necessary.
  • Joint fluid analysis, which involves using a needle to removing a small amount of fluid an affected joint. This test can help diagnose or rule out gout and other types of arthritis that can cause swollen, inflamed joints.

The combination of medical history, physical exam, medical imaging, and lab testing can help a physician rule out or make the diagnosis of psoriatic arthritis. The sooner an accurate diagnosis is made, the sooner treatment can begin.

Psoriatic arthritis: Diagnosis and treatment

How is psoriatic arthritis diagnosed?

A single medical test is not available to diagnose psoriatic arthritis. To find out whether you have psoriatic arthritis, your doctor will do the following:

  • Look at your medical records.

  • Ask you specific questions. This usually includes questions such as whether any of your blood relatives have psoriasis or psoriatic arthritis.

  • Examine your joints. This examination includes looking at your body to see whether you have swollen joints. Your doctor will gently press on the skin around certain joints to find out whether the area is tender.

  • Send you for medical testing. This may include x-rays and a blood test.

Before giving you a diagnosis, your doctor considers your test results and everything he or she learned while meeting with you. In case you’re wondering, the result from your blood test cannot tell whether you have psoriatic arthritis. It tells your doctor whether you have inflammation throughout your body. People who have psoriatic arthritis have body-wide inflammation. Many other diseases also cause body-wide inflammation. Inflammation is a piece of the puzzle.

Because psoriatic arthritis can look like other types of arthritis, patients often see a dermatologist or rheumatologist for a diagnosis. A rheumatologist is a medical doctor who specializes in diagnosing and treating arthritis and other diseases of the joints, muscles, and bones. Rheumatologists and dermatologists generally have the most experience diagnosing and treating psoriatic arthritis.

If you are diagnosed with psoriatic arthritis, it is important to know that treatment can:

  • Ease swelling, pain, stiffness, and other symptoms

  • Stop the arthritis from getting worse and damaging your joints

  • Improve your quality of life

How is psoriatic arthritis treated?

Today, there are many treatment options for psoriatic arthritis. A treatment plan often includes several of the following:

  • Therapy (physical, occupational, massage)

  • Patient education

  • Exercise and rest

  • Devices to protect joints

  • Medicine

  • Surgery

Therapy (physical, occupational, massage): These therapies can reduce pain. They can make it easier to move and do everyday tasks. If therapy can help, your doctor will write a prescription for the type(s) of therapy you need. Your therapist will work with your doctor and report your progress.

Patient education: Learning about psoriatic arthritis is important. The more you know, the better you can control this disease. Take time to learn the signs and symptoms. Ask your doctor what you should do when the arthritis flares. Learn about arthritis-friendly exercises and exercises that you should not do, at least for a while.

Exercise and rest: Each plays an important role. Arthritis-friendly exercises can help reduce pain, make it easier to move, and sometimes restore lost movement. Rest is important when psoriatic arthritis flares.

Devices to protect joints: Braces, splints, and supports can protect affected joints and prevent further damage. They offer support for painful areas and can stop painful movements. You should not buy one without first talking with your doctor. The device must fit you properly. It must support the area that needs support. Your doctor may recommend that a physical or occupational therapist fit you.

Medicine: Medicine can reduce swelling and ease pain. A few medicines can prevent the arthritis from worsening. The medicines that are often part of a treatment plan for psoriatic arthritis follow.

When psoriatic arthritis is mild, patients usually can reduce signs and symptoms with:

  • Non-steroidal anti-inflammatory drugs (NSAIDS) (pronounced en-saids): These help reduce swelling and pain. Some NSAIDs that may be part of a treatment plan for psoriatic arthritis do not require a prescription. These include aspirin, ibuprofen, naproxen, and nabumetone.

    Prescription NSAIDs include arthritis medicines such as celecoxib.

    Some people see their psoriasis worsen when they begin taking an NSAID. If this happens, call your dermatologist.

Tip: Take medicine after a meal

If you are taking aspirin or another medicine in the NSAID family, take the medicine immediately after you drink a glass of milk or eat a meal. This helps to protect your stomach. You should not drink alcohol when an NSAID is part of your treatment plan.

  • Shots of corticosteroids: When arthritis develops in a few joints, injecting this medicine into the swollen joints can quickly reduce swelling and pain.

Some people require stronger medicine to control their psoriatic arthritis. Your doctor may prescribe a disease-modifying, anti-rheumatic drug (DMARD) (pronounced dee-mard). DMARDs also reduce swelling and pain. Some DMARDs can prevent the arthritis from worsening and destroying joints. DMARDs that may be part of a treatment plan for psoriatic arthritis include:

  • Methotrexate: This medicine can reduce swelling in the joints and also is approved to treat psoriasis.

  • Injectable biologics: This type of medicine can prevent the arthritis from progressing and destroying the joints. Some of the biologics approved to treat psoriatic arthritis also can treat psoriasis.

To provide you with the most effective treatment, your doctor may prescribe two DMARDs. Prescribing both methotrexate and a biologic can help patients who have extensive or aggressive psoriatic arthritis. This combination has become a standard of care for aggressive psoriatic arthritis.

All medicine can cause side effects. Before taking a medicine, ask your doctor about possible side effects.

Surgery: If you have badly damaged joints or medicine does not help, surgery may be an option. Surgery can lessen pain. It can help you move more easily. It can improve the appearance of damaged joints. After surgery, you may be able to perform everyday tasks more easily. Surgery requires downtime. It involves some risk.


Following a treatment plan helps to reduce the signs and symptoms of psoriatic arthritis. Some medicines also can help prevent the arthritis from destroying the joints. There is currently no way to know whose psoriatic arthritis will later destroy joints. This is why doctors recommend an early diagnosis and proper treatment.

All content solely developed by the American Academy of Dermatology

Supported in part by Novartis.

Bloodwork for PsA: What Do the Results Mean?

I find it very interesting that biologics are a type of DMARD. The med I have taken the most has been methotrexate which I was on for many years. I kind of phased out of it a few years ago. I still take sulfasalazine though I have been without it for almost a month because the supply was not adequate at the pharmacy. My regular pharmacy transferred my prescription to another one, hoping they would be able to procure it more easily.

Come to find out the problem was that I was on the extended release sulfasalazine and that was the one where the shortage is occurring. I don’t know why it took this long for them to figure everything out! I was especially aggravated to find out that though I had called my doctor’s office and left a message at least four times for the nurse that she was not aware I was completely out.

When they finally figured out that the problem was the extended-release designation, now they got going again. But during this interim I know that there has been joint damage that has occurred and I have been having more problems with my bladder and urination from the extra inflammation present.

The doctor tried to tell me I could take Tylenol but of course that is silly because Tylenol is not for inflammation at all! I did briefly try turmeric which is supposed to be a natural diuretic. I counseled with my pharmacist about any possible negative reactions before doing that. I have found that the pharmacist tend to know more about these drugs then the doctors do. I guess that makes sense because they are so heavily into those areas current, and that is what they have studied on for the entire course of their study and preparation for the job.

As for the biologics when I first was recommended to take those they wanted me to be on enbrel but at that time it was still so new there were not enough factories to produce the supply needed. So we were directed off to other biologics, in my case remicade.

I was on remicade for four years. the very first time I took it my hands which had been painful or not painful at all within just a few hours. The doctor said that was not possible, but I know it was because it happened!

As for side effects I had very few, that was mainly being just a small headache during infusion and often feeling kind of like I had the flu for a few days afterwards. It was actually kind of fun getting the infusion in a way because I was at a clinic where I had my own room, TV, and Got a nice lunch. I used to say it was kind of like going to a spa if it wasn’t for the fact that I was being filled with ultimately harmful drugs. LOL

after the four years we moved to another state and in the transition between Medicaid programs the remicade infusions kind of dropped through the cracks. the doctor said that because I had not been on remicade for so long that I could not start it again because it would cause an allergic reaction. We have since talked about going on to another biologic but I’m nervous about that because I have a heavy history of cancer in my family so I’m kind of having to do the cost versus benefit decision making. if we do go on with the biologic it will most likely be simponi.

I also had discovered glucosamine and chondroitin combo which seemed really help the symptoms. I took that faithfully until the pharmacy where I I was able to buy them at a good cost closed. After that time I eventually started getting a little worse again and ended up moving from that biologic to higher doses of methotrexate.

I had started taking methotrexate far back in the course of my treatment but just in small amounts like little drops in water. But now with the higher dosage as they began to see problems with my liver. So for the doctor decided to put me on the injections .

I had always hated needles and so had a hard time getting going on that but eventually was able to do pretty well. Then I ended up getting the otrexup device which was even better. I was on that for quite a long time until one month for some reason I did not seem to be able to get through my skin after repeated attempts. I had also noticed that the pain level have gone down considerably and so I did eventually stop the methotrexate entirely. I did watch my blood work to make sure that information was not recurring at a high level.

I hope my initial posts are not too long. I guess I’m just excited to have found this group and be able to commiserate with those who are dealing with the same kinds of things that I am 🙂

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