2)  Rheumatoid Factor (RF) 

Rheumatoid factor (RF) is a type of antibody generally found in the blood of patients suffering from rheumatoid Arthritis.  However, in some cases, RF is also found in normal human beings.

Indication for Rheumatoid Factor

1. When symptoms of rheumatoid Arthritis appear.

2. Other conditions as stated in increased levels.

Normal Range 

In Titers                 1:20  or less 

In Units :                < 25 

High Level of Rheumatoid Factor in Blood

Ø      Increased level  means a person may be suffering from rheumatoid Arthritis, 

         provided other symptoms of rheumatoid Arthritis exist.

Ø      High level of rheumatoid factor is also found in conditions such as scleroderma, 

        systemic lupus erythematosus, sarcoidosis, endocarditis and mononucleosis.

High level of RF does not necessarily mean that a person is suffering from rheumatoid Arthritis.  In older people, a slight increase in RF is generally found.  Also some people suffering from rheumatoid  Arthritis may not have increased level of  Rheumatoid Factor.

3) ANA (Antinuclear Antibodies) 

ANA is a type of antibody generally found in the blood of patients suffering from SLE (systemic lupus erythematosus).  About ninety-five per cent of SLE patients have a positive ANA test.  However, a false positive test occurs in elderly people.  Some people with a family history of autoimmune disease may have a high ANA titer.  Also, a positive result does not always mean Rheumatoid Arthritis.  Sjogren’s syndrome, liver disease, scleroderma and other conditions may be associated with an elevated ANA

Indication for ANA 

1. When symptoms of SLE appear, such as Arthritis and rash.

2. To diagnose other autoimmune diseases.

3. Other conditions as stated in increased levels.

Normal Range 

In Titres :                               1:20 or less

(A Titer  is a measurement of the amount or  concentration of a substance in blood.)

High Titre of ANA in Blood 

Ø       Increased titre means a person may be suffering from SLE – a form of 

          arthritis- provided other symptoms of SLE exist.

Ø       High level of  ANA titre in blood may be found in rheumatoid Arthritis, 

         scleroderma,  sjogren syndrome, Raynaud’s disease, and juvenile 

         chronic Arthritis.

Ø       Certain drugs also increase titre in blood such as Isoniazid, Penicillin, 

          Tetracycline, and Diuretics. 

A negative ANA result makes SLE an unlikely diagnosis .  It has been seen that ANA is positive in : 

1.        90% or more cases – SLE.

2.        50% - 90% of cases – Sjogren’s syndrome, scleroderma, drug-induced 

           SLE, chronic active hepatitis.

3.        <50% of cases – Rheumatoid Arthritis, rheumatic fever, dermatomyositis, asbestosis, polyarteritis, nodosa, biliary cirrhosis, myasthenia gravis.

4) Joint Fluid Analysis 

Joint fluid or synovial fluid analysis is used primarily to determine the type of  etiology of joint disorders.  It is usually done to detect the cause of pain and inflammation in the joint.  As in the case of some form of Arthritis, synovial fluid increases in the joint causing pain and inflammation.  The analysis of synovial fluid helps in distinguishing different forms of Arthritis and to determine the exact cause of joint pain. Synovial fluid is removed from the joint with the help of a needle.

The tests that are generally performed on synovial fluid are red cell count, white cell count and differential, microscopical examination of crystals, gram stain and culture and sensitivity, measurement of protein, glucose, and lactate.  Lactate level is used to differentiate between inflammatory and septic

Arthritits and also does not require comparision with serum levels.

Indication for Joint Fluid Analysis 

1)       When symptoms of Arthritis appear with joint pain and swellings.

2)       Other conditions as stated in abnormal range.

Normal Range 

1)       Blood cell count : Red blood cell count less than 2000 mm³, white blood cell  

          count less than 200 mm^3.

2)       Crystals : Nil

3)       Gram stain and culture : No bacteria are seen

4)       Protein : < 3 g / dL

5)       Glucose :>/= 40 ug/dL

6)       Lactate :5-20 mg/dL (0.6-2.0 mmol/1)

Abnormal Range 

1)      Blood cell count :

           I.  Large number of red cells – haemophilic Arthritis or bleeding in the joint, 

               tumours of the joint.

          II.  Large number of white blood cells – More than 200 mm³ and less than 5000 mm³  

               in non-inflammatory disorders, such as osteoarthritis and less than 100000 mm³  

               in inflammatory disorders such as rheumatoid Arthritis.  In acute bacterial Arthritis, 

               white cell count may go up to 200000 mm³ .

          III.  In differential white cell count, neutrophil is elevated in bacterial Arthritis, rheumatic

               fever, gout, and rheumatoid Arthritis, while as elevated lymphocytes, it is usually

               seen in non-septic inflammation. 

2)      Crystals : Present

           I.      Monosodium Urate ( MSU) – Arthritis due to gout.

          II.      Calcium Pyrophosphate – pseudogout.

         III.      Cholesterol crystals – rheumatoid Arthritis or tuberculours Arthritis.

         IV.      Apatite crystals – synovitis. 

3)      Gram stain and culture : Bacteria seen and growth of bacteria in the culture – infection.

4)      Protein : >/= 3 g/dL –  infection or inflammation or haemorrhagic disorders

5)      Glucose : < 40 ug/dL – inflammatory or septic joint disorders.

6)      Lactate :

          I.      2.0 and < 7.5 mmol/1 – inflammatory joint problems.

        II.      > 7.5 mmol/1 – xeptic Arthritic but also seen in rheumatoid Arthritis. 

5)  Arthrography 

Arthrography is usually done to examine tendons, ligaments and  cartilage to evaluate any joint pain or to detect the cause behind 1\any abnormal movement of  the joint.  In arthrography, X-rays are taken of a joint after injecting a substance into the joint. It is more useful than a simple X-ray, since it can detect problems in the soft tissues of the joint that is not possible in a simple X-ray.  MR-arthrography or CT-arthrography is also used to provide a more clear-cut picture of a joint.

Indication for Arthrography 

1)       The tendons, ligaments or cartilage are damaged.

2)       The joint capsule appears to be enlarged.

3)       Presence of abnormal growth.

4)       The joints are displaced.

6)  Arthroscopy 

Arthroscopy is used to find the cause of joint pain or inflammation by viewing an interior of the joint through an arthroscope.  It may also be called joint endoscopy.  In this process, a small incision is made into the skin over the joint.  Through the incision, the arthroscope and other tools are inserted to view the interior of the  joint.

Indication for Arthroscopy 

1.        To find and evaluate a joint pain not explained with other tests.

2.        To remove floating pieces of cartilage

3.        To repair damaged ligaments

4.        To perform surgery to repair  severe joint problems.

Normal Range 

The ligaments and cartilage are smooth and white.

Abnormal Range 

1. Abnormal colour and shape of ligaments and cartilage.

2. Presence of abnormal growth.

3. Existence of infection or inflammation.

7) Alkaline Phosphatase (ALP) 

Alkaline phosphatase (ALP) is used primarily to evaluate bone and liver disorders.  It is an enzyme, produced primarily in the liver and bone.  It is also produced by the placenta of a pregnant woman, and to a lesser extent, by the intestines and kidneys.  In some bone diseases, such as a disorder called Paget’s disease ( where bones become enlarged and deformed), or in certain cancers that spread to the bone, ALP may be the only test result that is high.

Indication for Alkaline Phosphatase 

1. To evaluate bone abnormalities.

2. Other conditions as stated in increased and decreased levels.

Normal Range 

Adults 38-126 IU/L

High Level of Alkaline Phosphatase in Blood 

1. Increased level is seen in bone diseases, such as osteomalacia, Paget’s disease, bone tumours and hyperparathyroidism.

2. High level may result from liver disease such as hepatitis, obstructive jaundice, gallstones and cirrhosis.

3. Due to certain drugs such as allopurinol, methyldopa, tetracycline, isoniazid, indomethacin and chlorpromazine.

Low Level of Alkaline Phosphatase in Blood 

• Low level may be due to scurvy or celiac disease.

8)  C-Reactive Protein (CRP) 

CRP is used to assess how active the inflammation is in some form of Arthritis and other inflammatory diseases.  If CRP is reducing, it means you are getting better.

Indication for CRP 

1)       When inflammation is suspected.

2)       To evaluate the treatment for any inflammatory disease.

3)       To detect presence of an infection after any surgical procedure.

4)       Other conditions as stated in increased level.

Normal Range 

Adults : < 1mg/dL (However, most infections result when CRP > 10 mg/dL

High Level of CRP in Blood 

• 90% or more cases – rheumatic fever, rheumatoid Arthritis, SLE, acute bacterial infections, and viral hepatitis.

• 50%-90% of cases – gout, cancer, tuberculosis, and cirrhosis of liver.

• Less than 50% of cases – surgery, scarlet fever, varicella, and multiple sclerosis.

9)  Erythrocyte Sedimentation Rate (ESR) 

ESR is primarily used to detect the presence of infection or inflammation following an illness.  However, it does not provide any information regarding where the inflammation is and the cause behind it.  Also it may be affected without any specific  cause.  Hence, it is generally used with other tests just to give an idea about the presence of inflammation.

Indication for ESR

1)       To  detect the presence of infection and inflammation.

2)       To monitor the course of the disease

3)       TO find out the response to treatment.

4)       Other conditions as stated in increased and decreased rates.

Normal Range 

Westgren method :

            Male :      < Age 50  years : 0-15 mm/hr

               > Age 50  years : 0-20 mm/hr

Female:   < Age 50  years : 0-20 mm/hr

               > Age 50  years : 0-30 mm/hr

High Rate of ESR in Blood 

1)       Increased level of ESR may be associated with diseases such as polymyalgia rheumatica, temporal arteritis, acute myocardial infarction, thyroid disorders, chronic renal failure, and multiple myeloma.

2)       High level is also found in anaemia and pregnancy and with elderly people.

3)       Certain drugs also increase ESR such as theophylline, methyldopa, procainamide, penicillamine, high doses of vitamin A, and oral contraceptives.

Low Rate of ESR in Blod 

Decreased level of ESR is usually seen  in conditions such as sickle cell anaemia, lpolycythemia, congestive heart failure, and degenerative joint disease.

10)   Antistreptococcal Antibody Test (ASO Titre) 

ASO-Titre is generally used to confirm the diagnosis of a suspected streptococcal infection.

Indication for ASO Titre 

• When the symptoms suggest a streptococcal infection.

• To monitor the response to treatment for post-streptococcal illness.

• To differentiate between rheumatic fever from rheumatoid Arthritis.

Normal Range 

Children :               < 160 Todd Units / ml 

Adults :                  < 80  Todd Units / ml

High Level of ASO Titre in Blood 

• High level is generally seen in rheumatic fever, pharyngitis ( streptococcal), scarlet fever, otitis media, bacterial endocarditis, and glomerulonephritis.