Master's in Genetic Counseling (MGC)

Homocystinuria 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 homocystinuria in the state of Maryland is performed by the Guthrie bacterial bioassay to determine the level of methionine in the dried filter paper blood spot. A quantitative plasma amino acid profile and plasma homocystine levels are required for diagnostic testing.

The follow-up recommendations for homocystinuria screens in the state of Maryland are as follows:

Newborn Screening Result	Interpretation	Follow-Up Action Recommended
methionine <1 mg/dl	normal	none
methionine 1-2 mg/dl	borderline	A follow-up filter paper specimen is required within one week. If the follow-up specimen is abnormal, a quantitative plasma amino acid profile and genetic/metabolic consultation are required within one week. Report the patient to the Office for Hereditary Disorders at (410) 767-6730.
methionine >2 mg/dl	possible homocystinuria	A follow-up filter paper specimen is required within 48 hours. If the follow-up specimen is abnormal, a plasma amino acid profile and genetic/metabolic consultation are required within 48 hours. Report the patient to the Office for Hereditary Disorders at (410) 767-6730.

NOTE: The adequacy of this test depends on the baby having had 24 hours of protein containing feedings.

 

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