Pediatric Blood Specimens
Often, only a small volume of blood can be drawn from a pediatric patient. For maximum benefit from the limited sample, the specimen is handled individually, with special emphasis on micro techniques and procedures designed to conserve the specimen. Duplicate determinations (the standard procedure for assuring accurate results) may not be done if the sample is not large enough to perform all the requested tests.
This section describes special procedures for specimen collection from infants and children, and lists the minimum sample volume required for individual tests or test combinations. Please consult the tables before collecting the blood specimen.
All containers of patient specimens must be protected by plastic biohazard or similar bags during transportation to the laboratory. The requisition must be placed in the outside pocket of the bag. Do not staple the requisition to the bag.
OBTAINING BLOOD SPECIMENS FROM INFANTS
Warm the patient's foot with a warming device or towel (do not exceed 42 degrees C) for 10 minutes before obtaining sample.
Assemble the appropriate tubes for blood collection. If a micro collection container does not have the flo-top collector attachment, detach one from a microtainer that does.
Choose the appropriate lancet for heelstick. It is important to prick only the lateral aspect of the heel and never the medial aspect of the heel.
Cleanse the area thoroughly with alcohol and dry with sterile gauze before pricking. The depth of the cut is no more than 2.4 mm. Repeated lancing of the same area may result in macerations, skin breakdown, and increase the chance for infection. Deep puncture or lancing the curvature of the heel may result in osteochondritis. Lancing the medial aspect of the heel may result in puncture of the medial plantar artery.
Hold foot firmly to produce a good blood flow. Wipe off the initial drop of blood with sterile gauze to remove alcohol which may dilute specimen or hemolyze the RBC’s.
Touch tip of flo-top collector to the underside of drop; do not touch middle of drop. Blood should flow freely through the flo-top collector and down the tube wall. Allow blood to flow by gravity through the flo-top collector to the required volume. Avoid excessive milking of the puncture site, since this may cause hemolysis and contamination with tissue fluids.
For chemistry specimens, scraping too hard with the flo-top collector against the heel during collection may cause hemolysis.
For hematology specimens, tap the micro collection container gently after collection of each drop of blood to mix it with the anticoagulant and prevent clotting.
After drawing is done, remove flo-top collector and discard. Replace the lid and gently invert 8-10 times to ensure proper mixing of the sample.
Apply pressure on the wound using a sterile gauze pad until bleeding stops. Use a small adhesive dressing only if it is needed.
Place the labeled tube in a biohazard or similar specimen bag for delivery to the laboratory. The requisition must be placed in the outside pocket. Follow the procedures under the Delivering Specimens section of this manual.
Capillary collectors are not the same as Micro-hematocrit tubes. Capillary collectors are available in a lavender container (EDTA) for Hematology tests and amber or green containers for Clinical Chemistry procedures.
MINIMUM SPECIMEN REQUIREMENTS FOR PEDIATRIC TESTS
When collecting blood specimens (venous, capillary, arterial) from newborns, we recommend the use of green top microtainers with the plasma barrier. This tube type is our smallest volume blood collection tube, and will facilitate a maximum yield of plasma from whole blood. In addition, the minimum whole blood requirements listed below are based on an average hematocrit value of 50. The resulting volume of plasma after centrifugation and separation from the clot should meet the minimum amount of plasma required to do one analysis of the specimen.
Repeat analysis would require collection of additional blood samples.
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ASSAY
MIN. VOL SERUM/PLASMA
TUBE
Acetaminophen
120
1 SST Amber Microtainer (full 500µL)
Albumin
120
1 SST Amber Microtainer (full 500µL)
Anti HCV
200µL
2 SST 500µL full amber tube
Bilirubin (Total and/or Direct)
120
1 SST Amber Microtainer (full 500µL)
Blood Urea Nitrogen
120
1 SST Amber Microtainer (full 500µL)
BNP
200
2 EDTA lavender Microtainer
C ReactiveProtein High Sensitivity
300µL
2 SST 500µL full amber tube
Calcium
120
1 SST Amber Microtainer (full 500µL)
Carbamezepine
125
1 SST Amber Microtainer (full 500µL)
Carbon Dioxide
120
1 SST Amber Microtainer (full 500µL)
CD4/CD8 by Flowcytometry
200µL
500µL EDTA
Chloride
120
1 SST Amber Microtainer (full 500µL)
Cholesterol
120
1 SST Amber Microtainer (full 500µL)
Complement C3
300µL
2 SST 500µL full amber tube
Complement C4
300µL
2 SST 500µL full amber tube
Copper
600µL
1/2 royal blue top
Cortisol
130
1 SST Amber Microtainer (full 500µL)
Creatinine
120
1 SST Amber Microtainer (full 500µL)
Digoxin
160
1 SST Amber Microtainer (full 500µL)
Ferritin
140
1 SST Amber Microtainer (full 500µL)
FSH
Cannot use microcontainers for this test
FT4
140
1 SST Amber Microtainer (full 500µL)
G-6PD
150+ CBC
1 EDTA lavender Microtainer
Gentamicin
125
1 SST Amber Microtainer (full 500µL)
Glucose
120
1 SST Amber Microtainer (full 500µL)
HA1c
100µL
500µL EDTA
Haptoglobin
300µL
2 SST 500µL full amber tube
HCG
160
1 SST Amber Microtainer (full 500µL)
Hep A IgM
200µL
2 SST 500µL full amber tube
Hep A total Antibody
200µL
2 SST 500µL full amber tube
Hep B Core IgM
200µL
2 SST 500µL full amber tube
Hep B Core Total Antibody
300µL
2 SST 500µL full amber tube
Hep B Surf Antibody
300µL
2 SST 500µL full amber tube
Hep B Surf Antigen
300µL
2 SST 500µL full amber tube
Hepatis Panel Acute (HEPP)
800 µL
Four 500 µL amber tubes
Hepatitis Panel Source (HEPS)
1.0 mL
Five 500 µL amber tubes
HGBV-Hemoglobinopathy Variants
50 µL
500µL EDTA
Immunoglobulin A (IgA)
300µL
2 SST 500µL full amber tube
Immunoglobulin G (IgG)
300µL
2 SST 500µL full amber tube
Immunoglobulin M (IgM)
300µL
2 SST 500µL full amber tube
Insulin
125
1 SST Amber Microtainer (full 500µL)
Lead
120
1 EDTA lavender Microtainer
Magnesium
120
1 SST Amber Microtainer (full 500µL)
METB
120
1 SST Amber Microtainer (full 500µL)
METC
200
2 SST Amber Microtainer (full 500µL)
Phenobarbital
120
1 SST Amber Microtainer (full 500µL)
Phenytoin
120
1 SST Amber Microtainer (full 500µL)
Phosphorous
120
1 SST Amber Microtainer (full 500µL)
Potassium
120
1 SST Amber Microtainer (full 500µL)
Reumatoid Factor,
Quantitative300µL
2 SST 500µL full amber tube
Salicylate
120
1 SST Amber Microtainer (full 500µL)
Sodium
120
1 SST Amber Microtainer (full 500µL)
Theophylline
130
1 SST Amber Microtainer (full 500µL)
Tobramycin
160
1 SST Amber Microtainer (full 500µL)
TSH
350
3 SST Amber Microtainer (full 500µL)
Valproic Acid
140
1 SST Amber Microtainer (full 500µL)
Vancomycin
150
1 SST Amber Microtainer (full 500µL)
Vit B12test
300
Cannot use microcontainers for this
Zinc
600µL
1/2 royal blue top
Note: call Lab for minimum requirements on combination orders
METB: Na, K, CL, CO2, CREA, BUN, GLUC, CA, GAP, eGFR
METC: Na, K, CL, CO2, CREA, BUN, GLUC, CA, TBIL, TP, ALB, ALT, AST, ALKP, GAP, eGFR,
HEPP: HAIM, HBAG, HBCM, HCV
HEPS: HBAG, HBSB, HBCM, HBTC, HCV
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TRANSFUSION SERVICE
(BLOOD BANK) TESTS:
Pediatric Minimum, whole blood volume
(mL)
Type and Crossmatch
1
Use lavender top tube
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HEMATOLOGY TESTS:
Pediatric Minimum, whole blood volume(mL)
Maximum (mL)
COLLECTION CONTAINER – Lavender top tube (4 mL)
Complete Blood Count and platelet
1
4
Complete Blood Count, platelets and reticulocyte
1
4
Complete Blood Count with Sed Rate
3
4
Zinc Protoporphyrin
1
4
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HEMATOLOGY TESTS:
Pediatric Minimum, whole blood volume (mL)
Maximum (mL)
COLLECTION CONTAINER – Lavender top tube (2 mL)
Complete Blood Count with differential, reticulocyte, and platelets
0.5
2
MICRO COLLECTION CONTAINER – Pink top EDTA microtainer
Complete Blood Count, Differential, Platelet, and reticulocyte
0.3
0.5
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COLLECTION CONTAINER – Blue top tube (1.8 mL)
Prothrombin Time and/or Partial Thromboplastin Time, and/or Fibrinogen, (when hematocrits are less than 55%).
1.8
1.8
If the hematocrit is greater than 55%, obtain a special pediatric blue top tube kept in the nursery (6H) refrigerator. It contains 0.17 mL of sodium citrate and should be filled only up to the black line (2.25 mL of whole blood).
Note: This tube has no vacuum, so blood should be collected with a syringe then transferred into the tube up to the black line. This tube should be used when the hematocrit is 56 to 70%.
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MICROBIOLOGY TESTS
Pediatric Minimum, whole blood volume (mL)
Maximum (mL)
Blood Culture for bacteria or fungi
0.5 mL/bottle
(5 mL/bottle recommended)
10 mL/bottle
Blood Culture for Mycobacteria (bright green top tube)
3 mL
5 mL
Blood Parasites (lavender top tube)
3 mL
5 mL
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REFER TO THE ALPHABETICAL LIST OF TESTS FOR FURTHER INFORMATION. REFERENCE VALUES FOR PEDIATRIC PATIENTS WILL BE FOUND UNDER THE INDIVIDUAL TEST IN THE ALPHABETICAL LIST OF TESTS .