DOWNLOAD Test Reports
DDRC SRL Healthcare Packages

DDRC SRL Clinical Test

Under Your Tests...Empower Your Health

Antistreptolysin-o-aso



Why Get Tested

To help determine whether you have had a recent strep infection with the bacteria group A Streptococcus to help diagnose complications resulting from a strep infection such as rheumatic fever or glomerulonephritis a form of kidney disease

When To Get Tested

When you have symptoms such as fever chest pain fatigue and shortness of breath that suggest rheumatic fever or symptoms such as edema and dark urine that are associated with glomerulonephritis especially when you recently may have had a group A streptococcal infection that was not diagnosed and treated appropriately

Sample Required

A blood sample drawn from a vein in your arm

Test Preparation Needed

None




Common Questions


The ASO test is primarily used to help determine whether a recent strep infection with group A Streptococcus Is the cause of a person s or glomerulonephritis a form of kidney disease Caused rheumatic fever in a person with signs and symptoms The test may be ordered by itself or along with an anti-DNase B another test used to detect recent strep infections In most cases strep infections are identified and treated with antibiotics and the infections resolve In cases where they do not cause identifiable symptoms and or go untreated however complications sequelae namely rheumatic fever and glomerulonephritis can develop in some people especially young children The test therefore is ordered if a person presents with symptoms suggesting rheumatic fever or glomerulonephritis and has had a recent history of sore throat or a confirmed streptococcal infection Since the incidence of post-streptococcal complications has dropped in the U S so has the use of the ASO test

The ASO test is ordered when a person has symptoms that a health practitioner suspects may be due to an illness caused by a previous strep infection It is ordered when the symptoms emerge usually in the weeks following a sore throat or skin infection when the bacteria are no longer present in the throat or on the skin Some symptoms of rheumatic fever may include Fever Joint swelling and pain in more than one joint especially in the ankles knees elbows and wrists sometimes moving from one joint to another Small painless nodules under the skin Rapid jerky movements Sydenham s chorea Skin rash Sometimes the heart can become inflamed carditis this may not produce any symptoms but also may lead to shortness of breath heart palpitations or chest pain Some symptoms of glomerulonephritis may include Fatigue decreased energy Decreased urine output Bloody urine Rash Joint pain Swelling edema High blood pressure However these symptoms can be seen in other conditions The test may be performed twice with samples collected about two weeks apart for acute and convalescent ASO titers This is done to determine if the antibody level is rising falling or remaining the same

ASO antibodies are produced about a week to a month after an initial strep infection The amount of ASO antibody titer peaks at about 3 to 5 weeks after the illness and then tapers off but may remain detectable for several months after the strep infection has resolved A negative ASO or ASO that is present at very low titers means the person tested most likely has not had a recent strep infection This is especially true if a sample taken 10 to 14 days later is also negative low titer of antibody and if an anti-DNase B test is also negative low titer of antibody A small percentage of people with a complication related to a strep infection will not have an elevated ASO This is especially true with glomerulonephritis that may develop after a skin strep infection An elevated titer of antibody positive ASO or an ASO titer that is rising means that it is likely that the person tested has had a recent strep infection ASO titers that are initially high and then decline suggest that an infection has occurred and may be resolving The ASO test does not predict whether complications will occur following a strep infection nor does it predict the type or severity of the disease If symptoms of rheumatic fever or glomerulonephritis are present an elevated ASO level may be used to help confirm the diagnosis

Use of some antibiotics and corticosteroids may decrease ASO antibody levels

ASO levels are not detectable for at least a week after an infection so ASO tests are not used to diagnose a current acute infection A throat culture or a rapid strep test is the best method to diagnose strep throat streptococcal pharyngitis It is important that strep throat be promptly identified and treated to avoid complications and passing the infection on to others

No In general the ASO test is only performed when someone has symptoms suggesting that a complication may have developed after a strep infection that was not diagnosed and treated appropriately Most people do not experience these complications so the ASO test is not routinely done

Most doctors offices will not perform this test Typically your blood will be sent to a laboratory for testing