What does crystals in synovial fluid mean?

Asked By: Machelle Vaninadha | Last Updated: 8th May, 2020
Category: healthy living physical therapy
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Synovial fluid is evaluated under polarized light to recognize the presence of crystals and to distinguish the types of crystals that are present. Needle-like monosodium urate crystals are associated with gout and calcium pyrophosphate crystals are associated with pseudogout.

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In this regard, what microscopy technique is recommended for crystal identification on synovial fluid?

Polarised light microscopy of synovial fluid is an established diagnostic technique widely regarded as reliable for the detection of crystals. The threshold concentration of crystals which can be detected has been investigated and the sensitivity and specificity of six observers compared.

One may also ask, how do you interpret synovial fluid? Typical joint fluid findings

  1. Colour: Yellow.
  2. Clarity: Cloudy.
  3. Viscosity: Decreased.
  4. WBC: 2000–50,000 cells/mm3
  5. Neutrophils: >50 %
  6. Gram stain: Negative.
  7. Crystals: Positive. Gout – needle negative birefringent crystals. Pseudogout – rhomboid positively birefringent crystals.

Consequently, what is the normal WBC count in synovial fluid?

WBC count is one the most frequent tests performed on synovial fluid. Normally, synovial fluid contains less than 200 cells/µL. This count increases significantly in infections and inflammation.

What does a high nucleated cell count mean in synovial fluid?

The presence of uric acid crystals in the synovial fluid indicates gout. The presence of calcium pyrophosphate crystals in synovial fluid indicates pseudogout. A white blood cell count that is higher than normal may indicate infectious arthritis, gout, or rheumatoid arthritis.

39 Related Question Answers Found

What causes calcium pyrophosphate deposition disease?

Calcium pyrophosphate deposition disease (CPDD) is a metabolic arthropathy caused by the deposition of calcium pyrophosphate dihydrate in and around joints, especially in articular cartilage and fibrocartilage (see the images below).

What is positive and negative birefringence?

Positive or negative
Uniaxial birefringence is classified as positive when the extraordinary index of refraction ne is greater than the ordinary index no. Negative birefringence means that Δn = ne − no is less than zero.

Do cholesterol crystals polarized?

Similar to the cholesterol crystals seen in urine, synovial fluid cholesterol crystals appear as large, flat plates with notched corners and are highly birefringent under direct polarized light. Cholesterol crystals are too large to be phagocytized.

What color are gout crystals?

Characteristic Monosodium urate crystals Calcium pyrophosphate dehydrate crystals
Birefringence Strong Weak
Shape Needle-like, sharp edges Rhomboid, rod-like
Color parallel to polarizer Yellow Blue
Color perpendicular to polarizer Blue Yellow

What does positively birefringent mean?


Definition of positive birefringence. : birefringence of a medium (as quartz) that transmits the ordinary rays with greater speed than the extraordinary.

What is Pseudogout versus gout?

Like gout, pseudogout is a form of arthritis that causes sudden joint pain and swelling. While gout is caused by uric acid crystals; pseudogout is caused by calcium pyrophosphate dehydrate crystals (CPPD). And though the two have similar symptoms, treatment is somewhat different.

What is negatively birefringent needle shaped crystals?

The other main type of crystal arthritis is that in which calcium pyrophosphate crystals are formed (pseudogout). Gout is a disorder resulting from high concentration of uric acid. Urate crystals – are negatively birefringent – they will appear a needle shaped crystals (image below).

What do urate crystals look like?

Uric acid crystals can be different types of shapes: barrel, plate-like, or diamond. They're typically orange-brown or yellow in color. They can be found in normal urine when caused by a protein-rich diet, which increases uric acid in the urine.

What does yellow fluid in the knee mean?

Normal joint fluid is viscous (sticky) and appears clear to light yellow. Cloudy joint fluid is abnormal and suggestive of inflammation or an infection. Bloody joint fluid is also abnormal and may be caused by trauma to the joint.

What is a synovial fluid analysis?


Synovial fluid analysis is a group of tests that examine joint (synovial) fluid. The tests help diagnose and treat joint-related problems.

What does infected synovial fluid look like?

Synovial fluid that is an abnormal color can indicate inflammation. Synovial fluid is usually clear and colorless, but abnormal fluid can appear cloudy and colored. This suggests that microscopic or chemical changes have occurred. In this case, a doctor may recommend additional analysis.

How do you increase your synovial fluid?

Foods high in antioxidants can help reduce the rate of cartilage breakdown.
  1. Oily fish. Oily fish can reduce joint pain and morning stiffness, thanks to the anti-inflammatory omega-3 fatty acids they contain.
  2. Avocado.
  3. Turmeric.
  4. Extra virgin olive oil.
  5. Onions and Garlic.
  6. Grapefruit.
  7. Green Tea.
  8. Berries.

What happens to synovial fluid in rheumatoid arthritis?

The synovial membrane produces synovial fluid – a clear fluid that lubricates and nourishes the joint. Rheumatoid arthritis causes the normally thin synovium to become inflamed and thickened, leading to an accumulation of synovial fluid and causing pain and swelling.

Can synovial fluid be regenerated?

It acts as a shock absorber. It has no blood supply, so an injured cartilage takes a long time to heal and a damaged (lost) cartilage never gets regenerated naturally. Synovial fluid is a yolk like fluid that is produced by the synovial membrane that surrounds the inner linings of the joint.

How do doctors drain fluid from knees?


Joint aspiration is a procedure to remove fluid from the space around a joint using a needle and syringe. This is usually done under a local anesthetic to relieve swelling and/or to obtain fluid for analysis to diagnose a joint disorder or problem. Joint aspiration is most often done on the knee.

How much synovial fluid is in a joint?

The amount of synovial fluid present in a joint is very little—about 0.5–4 ml within large joints such as the knee—and this is spread throughout the joint by structures such as the cartilage, menisci and fat pads.

How do you test for synovitis?

Synovial Fluid Analysis
  1. To help diagnose the cause of joint inflammation, pain, and/or swelling.
  2. When one or more of your joints are swollen, red, and/or painful.
  3. A synovial fluid sample is obtained by inserting a needle into the space between the bones at a joint.