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Useful For
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The manual differential count is performed to determine/verify the relative count (percentage) of each subtype of circulating white blood cells. It is performed as a re-check for the automated count in cases of machine flags, abnormal counts & abnormal/atypical cells. Interpreted by lab technical staff/ Hematopathologist.
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Method name and description
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In manual differential, a Romanowsky stained blood smear is examined under a microscope and white blood cells are counted and classified based on their appearance which include neutrophilic stages (segmented neutrophils, band, metamyelocyte, myelocyte, promyelocyte), blast, lymphocytes, monocytes, eosinophils, basophils and other abnormal cells.
Microscopic examination is performed on thin peripheral blood smear stained with Romanowsky stain.
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Clinical information
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These counts are used as clinical guides in the diagnosis & monitoring of various hematologic and non-hematologic disorders.
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Specimen type / Specimen volume / Specimen container
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Whole blood. Smears spread from EDTA (may be part of the CBC).
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Collection instructions / Special Precautions / Timing of collection
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Container/Tube: EDTA.
Specimen Volume: 3-4 ml.
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Relevant clinical information to be provided
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Presence of lymphadenopathies, hepatomegaly, splenomegaly, skin lesions, etc.
Recent history of blood transfusion.
History of medications that might affect blood cells count/morphology including chemotherapeutic drugs.
Previous history of hematologic or non-hematologic neoplasms.
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Storage and transport instructions
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Ambient/Refrigerated (specimens are stable for 24 hours if stored at room temperature and 48 hours if stored at 2-8°C) . Specimen should not expose to extrem cold or hot weather during transportation.
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Specimen Rejection Criteria
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Insufficient quantity of blood (<1ml in macrotubes & <0.5ml in microtubes)
Errors in patient identification.
Delayed (old) specimen.
Clotted specimen/hemolyzed sample.
Wrong/unlabeled collection container.
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Biological reference intervals and clinical decision values
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Haematological Values For Normal Infants, Children and Adults
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Age
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0 - 2 days
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2 days and 1 sec. to 6 days
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6 days and 1 sec. to 13 days
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13 days and 1 sec. to 30 days
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30 days and 1 sec. to 60 days
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60 days and 1 sec. to 90 days
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3 mos. and 1 sec. to 6 mos.
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6 mos. and 1 sec. to 2 yrs.
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2 yrs. and 1 sec. to 6 yrs.
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6 yrs. and 1 sec. to 12 yrs.
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Adults
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Neutro
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4 - 14
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3 - 5
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3 - 6
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3 - 7
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3 - 9
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1 - 5
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1 - 6
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1 - 7
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1.5 - 8
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2 - 8
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2 - 7
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Lympho
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3 - 8
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2 - 8
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3 - 9
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3 - 9
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3 - 16
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4 - 10
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4 - 12
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3.5 - 11
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6 - 9
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1 - 5
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1 - 3
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Mono
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0.5 - 2
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0.5 - 1
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0.1 - 1.7
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0.1 - 1.7
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0.3 - 1
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0.4 - 1.2
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0.2 - 1.2
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0.2 - 1
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0.2 - 1
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0.2 - 1
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0.2 - 1
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Eoso
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0.1 - 1
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0.1 - 2
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0.1 - 0.8
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0.1 - 0.9
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0.2 - 1
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0.1 - 1
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0.1 - 1
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0.1 - 1
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0.1 - 1
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0.1 - 1
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0.02 - 0.5
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Baso
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0.02 - 0.1
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Notes:
Ranges are derived from Dacie and Lewis Practical Haematology, Twelfth Edition by Barbara J. Bain, Imelda Bates, Michael A. Laffan, Elsevier, except for the following:
*Adjusted according to NICU team recommendation to accommodate definition of Polycythemia (> 65%) (Cloherty and Stark's Manual of Neonatal Care, South Asian Edition by Eric C. Eichenwald, Anne R. Hansen, Camilia R. Martin, Ann R. Stark. SAE Editor, Naveen Jain, Copyright@ 2021 by Wolters Kluwer Health (India)
**Obtained from Alberta (https://www.albertahealthservices.ca/assets/wf/lab/wf-lab-edm-hematology-reference-ranges.pdf)
*** For RDW, for age group 0 - 12 years; and for MPV, ALL age group, Obtained from Pediatric Reference Intervals (Seventh Edition), Edited by Steven J. Soldin, Edward C. Wong, Carlo Brugnara, and Offie P. Soldin, AACC Press
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Factors affecting test performance and result interpretation
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Aged specimen, improper transport temperatures, excess EDTA, leukocytes clumping.
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Turnaround time / Days and times test performed / Specimen retention time
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2 working days / Test performed Daily 24/7.
Normal.slides are retained for 1 month.
Abnormal cases are retained for longer time according to space availability.
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