Congenital Hypothyroidism Screening in Maryland
The state of Maryland has a two specimen screening protocol. The initial specimen is drawn after the baby has had 24 hours of protein containing feedings, and the subsequent specimen is usually drawn between one and four weeks of age.
Screening for congenital hypothyroidism in the state of Maryland is performed by radioimmunoassays to determine the level of thyroxine (T4) and thyroid stimulating hormone (TSH) in the dried blood spot. Diagnostic testing consists of T4, Free T4, T3, TSH, thyroid binding globulin (TBG), antithyroid antibodies, a bone age, and a thyroid scan.
The follow-up recommendations for congenital hypothyroidism screens in the state of Maryland are as follows:
For Healthy, Full-term Newborns
| Newborn Screening Result | Interpretation | Follow-Up Action Recommended
|
| T4 within 2 standard deviations of the mean for the run of newborns <1 week old, (usually approximately 10 mg/dl and never <6.5 mg/dl) and TSH <30 uIU/ml | normal | none |
| T4 2 standard deviations below the mean and TSH >30 uIU/ml but <100 uIU/ml | borderline, possible TSH surge | Check the age of the baby at the time the specimen was drawn. If the specimen was drawn on the first day of life, a TSH surge is likely. A follow-up filter paper specimen is required within one week. If the follow-up specimen is borderline or abnormal, obtain serum T4 and TSH, refer the patient for a pediatric endocrinology consultation within 48 hours, and report the patient to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH >100 uIU/ml | probable primary hypothyroidism | Obtain serum T4 and TSH and refer the patient for a pediatric endocrinology consultation within 48 hours. Report the patient to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH <30 uIU/ml | possible TBG deficiency, secondary hypothyroidism, or delayed TSH response | A follow-up filter paper specimen is required within one week. If the T4 is still 2 standard deviations below the mean, and the TSH is still <30 uIU/ml, obtain serum T4, free T4, TBG, and TSH, and refer the patient for a pediatric endocrinology consultation within one week. If the TSH on the follow-up specimen is >100 uIU/ml, obtain serum T4 and TSH, and refer the patient for a pediatric endocrinology consultation within 48 hours. If the TSH on the follow-up specimen is >30 uIU/ml but <100 uIU/ml, obtain a second follow-up specimen within one week. If the results of the second follow-up specimen are not normal, refer the patient for pediatric endocrinology consultation within one week. Report any patient referred to the consultant to the Office for Hereditary Disorders at (410) 767-6730. |
NOTE: Interpretation of test results depends upon the age and state of health of the infant.
Healthy Infants Older Than One Week
| Newborn Screening Result | Interpretation | Follow-Up Action Recommended
|
| T4 within 2 standard deviations of the mean for the run of babies older than 1 week (usually approximately 8 mg/dl and never
<4 mg/dl) and TSH <30 uIU/ml |
normal |
none |
| T4 2 standard deviations below the mean and TSH >30 uIU/ml but <50 uIU/ml |
borderline |
A follow-up filter paper specimen is required within one week. If the follow-up specimen is borderline or abnormal, obtain serum T4 and TSH, and refer the patient for pediatric endocrinology consultation within 48 hours. Report any patient referred to the consultant to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH >50 uIU/ml |
possible primary hypothyroidism |
Obtain serum T4 and TSH and refer the patient for a pediatric endocrinology consultation within 48 hours. Report the patient to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH <30 uIU/ml |
possible TBG deficiency or secondary hypothyroidism |
A follow-up filter paper specimen is required within one week. If the T4 on the follow-up specimen is 2 standard deviations below the mean and the TSH is <30 uIU/ml, obtain serum T4, free T4, TBG, and TSH, and refer the patient for pediatric endocrinology consultation within one week. If the TSH on the follow-up specimen is >50 uIU/ml, obtain serum T4 and TSH, and refer the patient for a pediatric endocrinology consultation within 48 hours. If the TSH on the follow-up specimen is >30 uIU/ml but <50 uIU/ml, obtain a second follow-up filter paper specimen within one week. If the result on the second follow-up specimen is not normal, refer the patient for a pediatric endocrinology consultation within one week. Report any patient referred to the consultant to the Office for Hereditary Disorders at (410) 767-6730. |
Premature, Low Birth Weight, And Sick Infants
| Newborn Screening Result | Interpretation | Follow-Up Action Recommended
|
| T4 within 2 standard deviations of the mean for newborns and TSH <30 uIU/ml | "normal" | Follow-up filter paper specimens are required per NICU protocol in Strobel S. and Keller C. Metabolic screening in the NICU population. Pediatric Nursing 19: 113-132 (1993). |
| T4 2 standard deviations below the mean and TSH >30 uIU/ml but <100 uIU/ml | premature, low birth weight or sick infant, or TSH surge | A follow-up filter paper specimen is required within one week. If the follow-up specimen is abnormal, call the pediatric endocrinology consultant and follow-up per endocrinology consultant. If the follow-up specimen is normal, follow-up per NICU protocol in Strobel S. and Keller C. Metabolic screening in the NICU population. Pediatric Nursing 19: 113-132 (1993). Report any patient referred to the consultant to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH >100 uIU/ml | possible hypothyroidism or TSH surge | Call the pediatric endocrinology consultant. Follow-up per consultant. Report the patient to the Office for Hereditary Disorders at (410) 767-6730. |
| T4 2 standard deviations below the mean and TSH <30 uIU/ml | premature, low birth weight or sick infant, or secondary hypothyroidism | A follow-up filter paper specimen is required within one week. If the follow-up specimen is abnormal, call the pediatric endocrinology consultant and follow-up per the pediatric endocrinology consultant. Report any patient referred to the consultant to the Office for Hereditary Disorders at (410) 767-6730.
|
NOTE: Always ascertain if the mother was on antithyroid medication. If so, a follow-up filter paper specimen is required within one week and on a weekly basis until the results are normal. If the results are not normal within 4 weeks, refer the patient for pediatric endocrinology consultation and report the patient to the Office for Hereditary Disorders at (410) 767-6730.
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State Screening Program Contacts /
Maryland Consultants
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