Congenital Adrenal Hyperplasia Newborn Screen, Blood Spot
Use
This test is used as a second-tier testing method for newborns who exhibit abnormal results in the initial screening for congenital adrenal hyperplasia (CAH). CAH is a group of disorders caused by inherited defects in steroid biosynthesis, most commonly due to 21-hydroxylase deficiency. It results in life-threatening salt-wasting crises and incorrect sex assignment in virilized females, making early diagnosis crucial. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) precisely quantifies steroids such as 17-hydroxyprogesterone, enhancing the identification of CAH and reducing false positives.
Special Instructions
Important: Birth weight, time of birth, and gestational age must be provided when submitting specimens. Specimen collection requires a blood spot collection card and adherence to proper drying and handling procedures to avoid specimen rejection.
Limitations
This screening test has a higher positive predictive value compared to immunoassays but can still produce false-positive results. Results indicating abnormal findings should prompt follow-up testing. It is crucial to utilize the correct collection method and approved filter papers, as improper specimen collection could lead to rejection or inaccurate results.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 57086-1
- 38473-5
- 53343-0
- 53345-5
- 53338-0
- 53341-4
- 53336-4
- 46758-9
- 8339-4
- 57715-5
- 76516-4
- 18771-6
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
2 Blood spots
Minimum Volume
1 Blood spot
Container
Blood Spot Collection Card
Collection Instructions
Do not use device or capillary tube containing EDTA. Fill at least 2 circles on the filter paper card with approximately 100 microliters of blood per circle. Allow blood to dry at room temperature in a horizontal position for a minimum of 3 hours. Avoid exposure to heat or direct sunlight, and do not stack wet specimens. Ensure the specimen remains dry.
Causes for Rejection
Blood spot showing serum rings or multiple layers, insufficient specimen, unapproved filter papers
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 90 days |
| Refrigerated | 90 days |
| Frozen | 90 days |