Specimen Handling | The Children's Hospital of Philadelphia

Hematology Laboratory

Specimen Information and Handling

Complete Blood Count with Differential (CBCD)

A complete blood count includes a platelet count, white blood cell (WBC) differential, platelet estimate and red blood cell (RBC) indices and morphology. Platelet estimates are visual confirmations of platelet counts from the blood smear. These are only done if a manual differential (diff) is necessary or if the analyzer has flagged the platelet count as being inaccurate. If the platelet estimate DOES NOT match the platelet count, then a manual platelet will be performed, and the manual platelet count will be reported. Peripheral blood smears are also checked for nucleated RBCs, which are erroneously counted as WBCs by the Coulter. A correction of the WBC count will be made after review if significant numbers of nucleated RBCs are present on the smear.


The analyzer performs Automated WBC differentials unless the count fails to meet certain established criteria or in special circumstances where a manual differential is required. Differentials are not routinely performed on Oncology in-patients between the hours of 4 p.m. - 6 a.m. If differential counts are necessary for Oncology patients between 4 p.m. - 6 a.m., the clinical service should contact the laboratory, and the laboratory will perform a modified differential. A modified differential reports only segmented neutrophils, band neutrophils, and "others". Modified differentials are also performed for Oncology inpatients on the weekends.


Minimum between 0.3 and 0.5 ml (above the first line and up to the second line) of unclotted blood in a lavender EDTA microtainer tube OR 1.5 ml of unclotted blood in a lavender EDTA Hemoguard tube. Volumes less than 1 ml in a Hemoguard tube will skew the blood to anticoagulant ratio, will give inaccurate results, and will be rejected by the laboratory.

Complete Blood Count (CBC)

Complete blood count with a platelet count and, if needed a platelet estimate. Platelet estimates will not be performed unless the count fails to meet certain established criteria.


Same as CBCD.

Erythrocyte Sedimentation Rate (ESR)

The test measures the distance that erythrocytes have fallen after one hour in a vertical column of anticoagulated blood under the influence of gravity. The ESR is a nonspecific test for the acute phase response and inflammatory processes. The ESR is offered 24 hours a day, 7 days a week. The turn-around time for completing this test is a least an hour and a half.


1 ml of whole blood, lavender top tube. If ordered with a CBC at least 1.5 ml of whole blood is required.

Monospot Test/Monolatex Test (MSP)

The MSP is a screening test for infectious mononucleosis, based on detection of heterophile antibodies. The test should not be used for children under 4 years, because they either do not produce any or do not produce enough antibody to generate positive test results.


2-ml whole blood, gold top (serum separator tube).

Osmotic Fragility Test (OSMOT)

This test is used to diagnose hereditary spherocytosis. It is sent out to ARUP, Monday through Friday, except holidays. Specimens must arrive to CLS before 2 p.m.


3-5 ml whole blood, dark green tube; sodium heparin. The laboratory requires two specimens: one tube from the patient and another tube drawn on a control subject not related to the patient.

Reticulocyte Count (RET)


If ordered alone, 0.3 - 0.5 ml of unclotted whole blood in a lavender EDTA microtainer tube. If ordered with a CBC or CBCD, 1.5 ml of unclotted whole blood in a lavender EDTA Hemoguard tube. Reticulocyte counts can be added up to eight hours after the blood has been received.

Routine Urinalysis (UAX)

Routine Urinalysis without microscopic examination unless the patient is on a research study where it is required. Requests for microscopic examination should be directed by phone to the lab. Otherwise, microscopic urinalysis will be performed by the laboratory personnel only if the protein is greater than trace, and/or if the blood, nitrite, or leukocyte is positive.


2-5 ml of random, clean catch urine.

Cerebrospinal Fluid Count / Cerebrospinal Fluid Differential (CSFCC/CSFD)

Differentials on counts are only done if the WBC is 6/ CMM or greater or unless Specifically requested. Oncology outpatient CSFs are done in the Wood Lab during The day shift between 8 a.m. and 4:30 p.m., with the sample arriving no later than 4:30 p.m.


1 - 2 ml of CSF in a CSF tube.

Body Fluid Cell Count/ Body Fluid Differential (BFCC/BFD)

The site of collection must be noted. Differentials on counts are only done if the WBC is 6/CMM or greater.


1 - 2 ml of fluid in EDTA lavender top tube. These fluids MUST go into some type of anticoagulant otherwise they will clot and NOTHING can save the specimen.

Hematology Criteria for Call Back

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