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– Sample collection – Assay – Data evaluation – Reporting.

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Presentation on theme: "– Sample collection – Assay – Data evaluation – Reporting."— Presentation transcript:

1 – Sample collection – Assay – Data evaluation – Reporting

2 Dried Blood Spot (DBS) collection for newborn screening –Timing –Blood collection –Package and transfer

3 PONZONE ET AL. J Pediatr Gastroenterol Nutr 46(5), 2008 Newborn with PKU on a diet without phenylalanine

4 Etiology: –Birth stress –Postnatalis éhezés –Low energy intake –Immature enzyme systems Clinical symptoms: –Weight loss –Increased nitrogen excretion (urine) Catabolism

5 Metabolite levels change related to time Maximal sensitivity and specificity: 2-6 days after birth

6 Time of blood collection nap óra Limited Acceptable Optimal (Newborn Screening in New York State, 2003)

7 Hypothyroidism: : 23/126 = 18,2% :28/129 = 21,7% Classic PKU: < 2007 ~1 / / Incidence

8 Criteria: 60 ml milk/formula intake ? Screening test for galactosemia – blood galactose level Repeated sample is needed 2 weeks and 60days after blood transfusion

9 –Feeding – parenteral feeding –Blood transfusion –Gestational age –Drugs Factors with influence on metabolite levels

10 Beküldő intézet (pecsét): Orvos (pecsétszám): Gyermek családi neve: ❏ ♂ ❏ ♀ Születési súly: Utóneve: └┴┴┴┘g Terhességi hét:└┴┘ Születési dátum: Vérvétel időpontja └┴┴┴┴┴┴┴┘ A vérvétel időpontjában a baba: □ 48 óránál idősebb □ 48 óránál fiatalabb □ koraszülött Figyelem! Kötelező □ transzfúzió a szűrővizsgálat □ 2. vérvétel megismétlése! Táplálás: □ anyatej □ tápszer □ parenter. Gyógyszerek: Anya családi neve:Utóneve: TAJ:Telefon: Irányítószám:Település: Utca, házszám: Szegedi Tudományegyetem, Gyermekgyógyászati Klinika Anyagcsere laboratórium Újszülöttkori szűrés 6720 Szeged, Korányi fasor Telefon: (06 62) Fax: (06 62) Correctly complete all the information on the card

11 Name: Birth date: Metabolic Laboratory, Dept. Pediatrics, Univ Szeged

12

13 Repeated testing –Gestational age < 32 weeks –Blood collection < 48 h after birth –Food intake < 60 ml –Blood tansfusion/parenteral feeding

14 Newborns, small infants (<9kg) –Heel –Do not puncture the fingers Larger infants (> 9kg) –Heel or lateral aspect of the big toe –Do not puncture the fingers –Stick fingers in children > 2 years of age Site of puncture

15 Safe

16 Clean site with alcohol Allow to air dry for 30 seconds Puncture to a depth less than 2 mm using a sterile lancet

17 Wipe away first blood with sterile gauze pad The initial drop contains tissue fluid that may dilute the specimen Allow another large blood drop to form

18 Lightly touch the filter paper to the large drop of blood

19 Avoid touching the spots

20 Allow to soak through and completely fill the circle Apply blood to one side of the filter paper only Do not layer successive drops of blood or apply blood more than once to the same collection circle

21 Fill remaining circles in the same manner with successive drops of blood If blood flow is diminished repeated puncturing may be necessary

22 Inspect card to ensure you have collected enough blood, and the specimen is valid Valid Specimen

23 Place filter paper on a horizontal surface and AIR DRY for at least 3 hours Keep away from direct sunlight, heat and dust Do not allow blood spots to come into contact with any surface or each other

24 Do not store, transport cards every day

25 Valid and invalid DBS

26 Invalid DBS

27 Assay

28 QC CDC: amino acids (Phe, Tyr), galactose, TSH 17OH-progesterone Interlaboratory Quality Assurance for Newborn Screening (Geesthacht, Germany): Phe, galactose ERNDIM:

29 Evaluation of data

30 Cut-off levels Sahai I, Marsden D: Crit Rev Clin Lab Sci 46(2):55-82,2009 Analyte concentration Mean (Normal) Mean (Affected) Cut-Off Affected Normal Population Mean (Normal) Normal Population Affected Fals Positives Fals Negatives True positives Number of neonates True Negatives

31 Screening test performance Sensitivity Specificity False negative rate False positive rate Positive predictive value Negative predictive value

32 Problems Incorrect blood sampling Repeated sample - parents not found

33 Screening assay Does not exclude all metabolic disorders Keep in mind

34 Second-tier tests Beutler-test BH4-assay T3, T4 Steroid profile

35 Mutation analysis Diagnosis Prognostic value Prenatal diagnosis

36 Protocols Analytical side- Clinical side screening therapy follow up

37 Anyagcsere betegségek újszülöttkori szűrése Szülői tájékoztató


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