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7 Cards in this Set
- Front
- Back
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What is a "Guthrie" newborn screening card?
- what sorts of tests can be done on samples collected in this way? |
27ul blood in a 9mm spot from which small samples are punched
- Bacterial inhib assays - fluorometric, colorimetric detection of analytes - electrophoresis - enzymatic analysis - radio-labeled assays - DNA-based analysis - mass spectrometry |
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How does a mass spectrometer work?
- is it fast for newborn screening? |
device that separates and quantifies ions based on their mass/charge ratio (m/z).
--> produces charged particles from the chemical substance being analyzed --> uses EM fields to separate and measure the mass of the charged particles --> produces a spectrograph of peaks - yes it is, req. ~2min per sample, and can test for multiple pre-selected analytes w/o extensive prep. |
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What are some dz classifications that are detectable by MS/MS screening?
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- amino acidopathies: PKU, maple syrup urine dz, homocystinuria, citrullinemia/argininosuccinic aciduria, tyrosinemia II, III
- organic acidemias - fatty acid oxidation disorders (FAO disorders) |
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What is isovalerylcarnitine (C5OH)?
- tests for? What do we measure to test for FAO dz? |
The analyte formed from leucine --> isovaleryl CoA --> <breakdown>
- used to test for Isovaleric acidemia (IVA) Acyl Carnitine |
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What do we do in the case of an abnormal result on the first test?
- if that comes back abnormal? |
retest that card
- either mark as borderline (which means we send results back to submitter in addition to requesting a repeat specimen) or mark as... abnormal (diagnostic result or a second borderline result) --> MS/MS lab calls the metabolic specialist. |
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Who is this newborn testing done on?
Does MS/MS screening detects disorders? Thus, what is necessary? Is this necessary w/ other forms of screening? - specificity? - can it identify pts who will never develop clinical dz? |
all infants unless a waiver is signed by the parents.
No, just abnormal concentrations of analytes. - follow-up dx testing is necessary to determine if an inborn error of metabolism exists. --> YES this is necessary with other types of screening! - v. high. - yes, though some will be normal at identification and then develop dz later. |
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What are the requirements for a NBS re: disorder, test, and follow-up?
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- disorder must be clearly defined, treatable (with a tx started in the neonatal period), and it must have a reasonable incidence
- rapid turnaround time, high sensitivity and specificity, small and easily obtainable sample, and a reasonable cost - Prompt, well-organized Provide definitive diagnosis Provide treatment, short- and long-term Provide a self-evaluation component |
