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When is a strep titer considered to be abnormal, or "elevated"?

Lynne Kenney
Psychology
The lab at the National Institute of Health considers strep titers between 0-400 to be normal. Other labs set the upper limit at 150 or 200. Since each lab measures titers in different ways, it is important to know the range used by the laboratory where the test was done – just ask where they draw the line between negative or positive titers.

It is important to note that some grade-school aged children have chronically “elevated” titers. These may actually be in the normal range for that child, as there is a lot of individual variability in titer values. Because of this variability, doctors will often draw a titer when the child is sick, or shortly thereafter, and then draw another titer several weeks later to see if the titer is “rising” – if so, this is strong evidence that the illness was due to strep. (Of course, a less expensive way to make this determination is to take a throat culture at the time that the child is ill.)

Since each lab measures titers in different ways, it is important to know the range used by the laboratory where the test was done – just ask where they draw the line between negative or positive titers.

It is important to note that some grade-school aged children have chronically "elevated" titers. These may actually be in the normal range for that child, as there is a lot of individual variability in titer values. Because of this variability, doctors will often draw a titer when the child is sick, or shortly thereafter, and then draw another titer several weeks later to see if the titer is "rising" – if so, this is strong evidence that the illness was due to strep. (Of course, a less expensive way to make this determination is to take a throat culture at the time that the child is ill.).

This answer is based on source  information from the National Institute of Neurological Disorders and Stroke.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.