What Makes a Satisfactory Newborn Screen Sample?

Transcription

1 What Makes a Satisfactory Newborn Screen Sample? Feb 21, 2013 Christine McRoberts Newborn Screening Ontario

2 One of the challenges the Newborn screening Ontario program (NSO) faces every day is the receipt of samples which are unsuitable for testing. NSO receives approximately 145,000 samples per year from submitting health care facilities and practitioners, approximately 2.6 % of which are unsatisfactory. That translates into greater than 3700 samples rejected annually.

3 Objectives Discuss rationale for insistence on high quality samples To establish the criteria of what makes a satisfactory newborn screen sample Discuss strategies to decrease the incidence of rejected newborn screening samples

4 Consequences of an unsatisfactory new born screen sample Risk of delaying the identification of a screen positive baby Additional stress to baby and family related to the collection of a second sample Parents may refuse the second collection attempt resulting in a missed screen Increased workload for the submitter in locating, retrieving and collecting the repeat sample Increased workload to NSO in processing, reporting and follow up for the unsatisfactory sample.

5 Unsatisfactory Samples Different types of Unsats : 1. Data Unsat 1. Incomplete/unreliable testing Ex. Sample taken at <24hours of age 2. Unable to report Ex. Missing critical information (eg. Date of Collection) 2. Unable to test Lab Unsat Ex. Sample was not of sufficient quality to test

6 Data Unsats The submitter is contacted for missing information if the information is not obtained within a reasonable time period, the sample is reported as unsatisfactory based on insufficient data. Samples may also be reported as unsatisfactory if taken when the baby is less than 24 hours old or if the sample was delayed in transit for >14 days. Samples taken< 24 hrs and those > 14 days old will be analyzed and reported out if positive. A repeat sample will be requested.

7 Expired Blood Dot Cards Each blood dot card has an expiry date, which can be found in the upper right hand corner of the card next to an hourglass symbol, under the circles for the blood. Before collecting the newborn screening sample, ensure that the blood card or collection device has not expired.

8 Unsatisfactory Laboratory Samples A"lab unsat. is a sample that is rejected due to insufficient quantity or poor quality. Laboratory unsats will not be analyzed as they may produce unreliable results.

9 Transportation of Dried Blood Spots To transport dried blood spot specimens you must use a triple packaging system: 1.) The primary container is the filter paper matrix that contains the absorbed and dried blood. 2.) The secondary is a fold over flap or inner envelope which secure the contents and encloses the filter paper. 3.) The third level of containment is an outer envelope of sturdy high quality paper, in our case the Can Par envelope. These levels of containment provide reasonable safety from occupational exposure and maintain optimal specimen integrity.

10 Ziploc bags and stapled requisitions It is not necessary to tape, staple or paperclip the protective flap to the blood collection card. The protective flap is sufficient to protect the sample. It is not necessary to bag the samples individually.

11 Sample Receipt Samples are delivered by courier to the NSO lab twice daily Monday Friday. Upon receipt in the lab, all blood card samples are reviewed for sample quality and quantity.

12 Sample Review A minimum of eight 3.2 mm punches must be available for the sample to be considered satisfactory. In an effort to minimize the number of rejected or unsatisfactory samples, any samples which are initially considered unsatisfactory are set aside and re evaluated by a second staff member before irrevocably being coded as unsatisfactory.

13 Notification of laboratory unsatisfactory samples Submitters are notified of the receipt of an unsatisfactory sample by telephone on the same day the sample is received in the lab. An unsatisfactory report is faxed within 24 hrs

14 Accessioning and Bar coding Each sample is bar coded with a unique identifier and separated into two segments. The bar coded demographic section is sent to the lab office for data entry. The bar coded filter paper segment (blood spot) remains in the lab to be assayed. The sample barcode links sample demographics entered in the NSO office to the sample results in the Lab Information System.

15 Sample Processing or punching Bar coded patient samples, calibrators and quality control material are punched into barcoded 96 well plates, each plate unique to a particular assay. As each sample barcode is scanned and punched into the 96 well plates at the multipuncher, requests are generated for each assay performed. A final report is not issued until all of the requests have been satisfied.

16 Good Sample Collection Front of Card Back of Card In order to ensure the successful completion of all assays on the Newborn Screening Ontario (NSO) panel, NSO requests submitters collect a blood collection card with five circles homogenously and completely saturated with blood.

17 3.2 mm punches are taken from the applied blood spots and used during the newborn screening process It is estimated that 75 ul of blood is required to fill one circle. With the exception of the screening test for hemoglobinopathies, the Newborn screening assays are quantitative or semi quantitative. Calculations used to determine the final concentration of the analytes in the blood spot assume that each 3.2 mm punch contains precisely 3.1 ul of blood. Any deviation from this volume could result in an unreliable newborn screen result.

18 Code 001:Quantity of blood insufficient Front of card Back of card Front of card appears sufficient, however blood has not completely saturated through to back of card. Remember to check that the blood applied to the front of the filter paper card has completely saturated through to the back of the card.

19 Code 002: Blood spots appear scratched or abraded The surface of the filter paper has been disturbed during a too aggressive application process. Because the surface of the filter paper on the blood collection card has been disturbed, we can no longer assume that the volume of blood in a 3.2 mm punch is 3.1 ul. During application of the blood to the card, try to drop the blood from the capillary tube or syringe without touching or disturbing the surface of the filter paper.

20 Capillary Applied Samples? Both of these blood spot samples were reported as Unsatisfactory Code 002. (Scratched and abraded). If blood spot collection is either venous or capillary, avoid touching the surface of the filter paper with the blood collection device.

21 Code :002 Capillary applied?

22 Use Of Anticoagulants If using a capillary or venous sample, please avoid the use of anticoagulants. Heparin has been indicated to interfere with the PCR reaction used during DNA based assays. EDTA is known to cause false positive screens for some of our immunoflourescence based assays and should not be used during the newborn screening blood collection process.

23 Code 003: Wet and discolored When collecting a newborn screening sample, before applying the blood to the collection card, ensure the heel is clean and dry to avoid any contamination or dilution of the sample.

24 Code 004: Blood spots are Supersaturated A positive screen may be the consequence of either an elevated or decreased result value. We cannot accept samples that have too much blood (supersaturated).

25 Code 005: Blood Spots appear diluted Diluted blood samples may produce results with normal analyte values resulting in a false negative screen in cases where a high value is considered out of range, which is the case for the majority of the disorders we are screening for.

26 Code 006: Blood spots exhibit serum rings Do not excessively squeeze or milk the puncture site.

27 Code 007: Blood spots appear clotted or layered Apply the blood quickly so that it does not clot during application to the blood card.

28 Code 007: Blood spots appear clotted or layered If after applying the initial drop of blood, it has not saturated completely through to the back side of the card, another blood drop may be applied to the same side of the card. Try not to overlap or layer the blood.

29 5 circles? If it seems unlikely a good blood spot will be achieved from the first application of blood, it is acceptable to move on to the next circle, this time trying to apply a larger blood drop, completely saturating the filter card. If a portion of the blood spots are in some way not suitable for analysis, but we are still able to identify eight good areas to successfully obtain satisfactory blood spots, we will accept the card.

30 It is better to successfully fill 2 or 3 of the circles on the blood card than to partially fill all five.

31 The reverse side of an accepted blood spot card that scarcely meets our criteria.

32 Another blood spot card that scarcely meets our criteria. Every effort will be made to avoid rejecting a newborn screening sample.

33 Please allow the sample to dry completely before closing the protective flap as the flap may adhere to the applied blood and disturbed the spot upon opening.

34 Thank you. Questions?