Should you get tested for Alpha-1?
Until it is appropriate to begin screening the general population for Alpha-1, there are some guidelines as to who should be tested for this condition. These include individuals with:
- A diagnosis of emphysema, chronic bronchitis, unexplained bronchiectasis, or chronic obstructive pulmonary disease (COPD)
- Family history of Alpha-1 Family history of emphysema, bronchiectasis, liver disease, or panniculitis
- Chronic asthma in which lung function does not return to normal with therapy in adolescents and adults
- Recurrent pneumonia or bronchitis Unexplained liver disease
- Granulomatosis with polyangiitis (GPA or C-ANCA positive vasculitis)
- Necrotizing panniculitis
If you have one or more of the above risk factors, it is recommended that you should be tested for Alpha-1.
Testing for Alpha-1
There are three types of simple laboratory tests for Alpha-1:
1) Serum level: This determines the amount of alpha-1 antitrypsin (AAT) protein in the blood.
The normal range of AAT in the blood can be as high as 400 mg/dL or 4 grams in each quart of blood. The level can be measured using one of a variety of techniques but, most commonly, antibodies against AAT are used to quantify the amount of AAT in the serum. The results are expressed either in mg/dL (milligrams per 100 cc of blood) or in μM (micromoles).
Local labs tend to use the mg/dL units and the normal range tends to vary from lab to lab, with the low end of the normal range varying from 70 to 200 mg/dL. In general, individuals with severe Alpha-1 deficiencies tend to have an AAT level of less than 50 mg/dL. The national testing laboratories use the μM system, and the low end of the normal range is approximately 28 μM in this system. Individuals with a level less than 11 μM are considered to have severe deficiency of AAT.
2) Pi-typing or phenotyping: Used to evaluate the chemical characteristics of the AAT protein in the blood since deficient AAT protein is different than normal AAT protein.
3) Genotyping: Used to observe the AAT genes and test them for common abnormalities.
It is often helpful to do two or even all of these tests in order to confirm an Alpha-1 diagnosis.
To find out more about each test and learn about other Alpha-1 diagnostic tools, please visit the Big Fat Reference Guide to Alpha-1. If you are enrolled in the AlphaNet Subscriber Portal, you can access the BFRG here.
You can get more information on Alpha-1 testing from a variety of resources: