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Test ID: Total Galactose DBS
Total Galactose DBS
Semi Quantitative determination of Total Galactose in dried blood spot for Galactosemia newborns screening
Useful For

Semi Quantitative determination of total galactose (galactose and galactose-1-phosphate) concentrations in blood specimens dried on filter paper as an aid in screening newborns for Galactosemia.

Method name and description

Neonatal Total Galactose test  is based on a fluorescent galactose oxidase
method. The assay measures total galactose, i.e. both galactose and galactose-1-
phosphate. 

Reporting name

Total Galactose DBS

Clinical information

α-D-galactose is metabolized via a series of sequential reactions called a Leloir pathway. The three enzymes that catalyze these reactions are galactokinase (GALK, EC 2.7.1.6), galactose-1-phosphate uridylyltransferase (GALT, EC 2.7.7.12), and UDP-galactose 4’-epimerase (GALE, EC 5.1.3.2). Deficiency in any one of these three enzymes in humans results in a form of an inherited metabolic disorder, galactosemia. The most common and clinically severe form of galactosemia is classic galactosemia which is due to GALT deficiency. The measurement of galactose and galactose-1-phosphate concentration in dried blood spots is performed to screen for deficiency in any of these three enzymes involved in galactose metabolism. 
Classic galactosemia affects about 1/30,000 – 1/60,000 live-births . If not diagnosed and treated within the newborn period, it can lead to diarrhea, dehydration, jaundice, hepatic failure, hypoglycemia, cataracts, and developmental retardation . Treatment of the disease consists of withdrawal of all foods containing lactose and galactose from the diet . 

Reference: GSP Neonatal Total Galactose kit package insert

Aliases

Neonatal Screening Test

Neonatal Screening Testing

Specimen type / Specimen volume / Specimen container

Specimen type: Whole blood collected from heel prick with direct application onto special Whatman 903 filter paper.

Specimen Volume: 5 Circles(spot) if ordered with the whole screening panel. Minimum 2 spot if requested alone i.e., successive collection.                                  

Specimen container: Newborn screening Blood Spot Collection Card 

Collection instructions / Special Precautions / Timing of collection

Collection instructions:

1.Collect blood for newborn screening at 24 hours of age.

2.Complete the required patient information on the collection card and ensure that the expiration date of the collection card has not passed.

3.Collect blood from the most medial or lateral portion of the plantar surface of the heel; allow blood to soak through to completely fill each of the preprinted circles; do not apply layers of successive blood drops to the same printed circle; inspect both sides of the collection card to be sure blood is soaked through to the back of the card.

4.Allow blood specimen to air dry for a minimum of three hours on a horizontally level, nonabsorbent, open surface at an ambient temperature of 18 to 25 °C .

5. Fold-over cover provides protection from contamination before blood collection, during specimen transportation and during specimen storage after analysis. Blood spots must be thoroughly dry before the flap is closed over spots.

6.The collection card/dried blood specimen should be transported to the laboratory with the appropriate tracking documentation and within 24 hours of collection.

Special Precautions

1.Premature infants who are less than 32 weeks of gestational age, screening must be repeated after the infant completes 32 weeks.  

2.In case of immediate blood transfusion, exchange transfusion, treatment with corticosteroids or dopamine initial specimen must be collected even if the newborn less than 24 hrs of  age and repeated after 5 days of discontinuation of drug or last transfusion.  

Relevant clinical information to be provided

Complete the required demographic information on the blood spot collection card.

 

Specimen Rejection Criteria

Specimen collected in expired Guthrie card. 

Specimen collected before 24 hours of newborn age.

Insufficient quantity of blood. 

Errors in patient identifiers.

Specimen spots were damaged or delayed ,received after seven (7)  days from the collection date.

Specimen appears scratched or abraded.

Specimen appears supersaturated.

Specimen appears diluted, discolored, or contaminated.

Specimen exhibits serum rings.

Specimen appears clotted or layered.

Applying blood using capillary tubes or using Anticoagulants (EDTA, citrate).

Specimens accompanied by improper or incomplete paperwork.

Using white ink on the blood specimen filter paper.

 

Biological reference intervals and clinical decision values

0 - 15 mg/dL

Factors affecting test performance and result interpretation

Galactose-limited diet.

False-negative screening results in infants on lactose-free formula and in those receiving total parenteral nutrition

Turnaround time / Days and times test performed / Specimen retention time

Turnaround time :3 working days.

Days and times test performed: Saturday -Thursday 7:00am-3:00PM

Specimen retention time: Indefinite