Davis's Lab & Diagnostic Tests

Complete Blood Count

Complete Blood Count is a topic covered in the Davis's Lab & Diagnostic Tests.

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Common Use:
To evaluate numerous conditions involving red blood cells, white blood cells, and platelets. This test is also used to indicate inflammation, infection, and response to chemotherapy.

Whole blood from one full lavender-top (EDTA) tube or Microtainer. Whole blood from a green-top (lithium or sodium heparin) tube may be submitted, but the following automated values may not be reported: white blood cell (WBC) count, WBC differential, platelet count, immature platelet fraction (IPF), and mean platelet volume.

Normal Findings:
(Method: Automated, computerized, multichannel analyzers. Many of these analyzers are capable of determining a five- or six-part WBC differential.) This battery of tests includes hemoglobin, hematocrit, red blood cell (RBC) count, RBC morphology, RBC indices, RBC distribution width index (RDWCV and RDWSD), platelet count, platelet size, IPF, WBC count, and WBC differential. The six-part automated WBC differential identifies and enumerates neutrophils, lymphocytes, monocytes, eosinophils, basophils, and immature granulocytes (IG), where IG represents the combined enumeration of promyelocytes, metamyelocytes, and myelocytes as both an absolute number and a percentage. The five-part WBC differential includes all but the IG parameters.

AgeConventional UnitsSI Units (Conventional Units × 10)
Cord blood13.5–20.7 g/dL135–207 g/L
0–1 wk15.2–23.6 g/dL152–236 g/L
2–3 wk13.3–18.7 g/dL133–187 g/L
1–2 mo10.7–18 g/dL107–180 g/L
3–6 mo11.7–16.3 g/dL117–163 g/L
7 mo–1 yr10.3–14.3 g/dL103–143 g/L
2–6 yr10–13.3 g/dL100–133 g/L
7–15 yr10.7–14 g/dL107–140 g/L
16–18 yr11–15 g/dL110–150 g/L
 Male14–17.3 g/dL140–173 g/L
 Female11.7–15.5 g/dL117–155 g/L
Pregnant Female
 1st Trimester11.6–13.9 g/dL116–139 g/L
 2nd and 3rd  Trimester9.5–11 g/dL95–110 g/L
Values are slightly lower in older adults.Reference range values may vary between laboratories.Note: See “Complete Blood Count, Hemoglobin” study for more detailed information.

AgeConventional Units (%)SI Units (Conventional Units × 0.01) (Volume Fraction)
Cord blood42–620.42–0.62
0–1 wk46–680.46–0.68
2–3 wk41–560.41–0.56
1–2 mo39–590.39–0.59
3–6 mo35–490.35–0.49
7 mo–1 yr31–430.31–0.43
2–6 yr30–400.3–0.4
7–15 yr32–420.32–0.42
16–18 yr33–450.33–0.45
Pregnant Female
 1st Trimester35–420.35–0.42
 2nd and 3rd  Trimester28–330.28–0.33
Values are slightly lower in older adults.Reference range values may vary between laboratories.Note: See “Complete Blood Count, Hematocrit” study for more detailed information.

White Blood Cell Count and Differential
AgeConventional Units WBC × 103/microLNeutrophilsLymphocytesMonocytesEosinophilsBasophils
(Absolute) and %(Absolute) and %(Absolute) and %(Absolute) and %(Absolute) and %
Birth9.1–30.1(5.5–18.3) 24%–58%(2.8–9.3) 26%–56%(0.5–1.7) 7%–13%(0.02–0.7) 0%–8%(0.1–0.2) 0%–2.5%
1–23 mo6.1–17.5(1.9–5.4) 21%–67%(3.7–10.7) 20%–64%(0.3–0.8) 4%–11%(0.2–0.5) 0%–3.3%(0–0.1) 0%–1%
2–10 yr4.5–13.5(2.4–7.3) 30%–77%(1.7–5.1) 14%–50%(0.2–0.6) 4%–9%(0.1–0.3) 0%–5.8%(0–0.1) 0%–1%
11 yr–older adult4.5–11.1(2.7–6.5) 40%–75%(1.5–3.7) 12%–44%(0.2–0.4) 4%–9%(0.05–0.5) 0%–5.5%(0–0.1) 0%–1%
*SI Units (Conventional Units × 1 or WBC × 109/L).Note: See “Complete Blood Count, WBC Count and Differential” study for more detailed information.

White Blood Cell Count and Differential
AgeImmature Granulocytes (Absolute) (103/microL)Immature Granulocyte Fraction (IGF) (%)
Birth–9 yr0–0.030%–0.4%
10 yr–older adult0–0.090%–0.9%

Red Blood Cell Count
AgeConventional Units (106 cells/microL)SI Units (1012 cells/L) (Conventional Units × 1)
Cord blood3.61–5.813.61–5.81
0–1 wk4.51–6.014.51–6.01
2–3 wk3.99–6.113.99–6.11
1–2 mo3.71–6.113.71–6.11
3–6 mo3.81–5.613.81–5.61
7 mo–1 yr3.81–5.213.81–5.21
2–6 yr3.91–5.313.91–5.31
7–15 yr3.99–5.213.99–5.21
16–18 yr4.21–5.414.21–5.41
Values are decreased in pregnancy related to the dilutional effects of increased fluid volume and potential nutritional deficiency related to decreased intake, nausea, and/or vomiting. Values are slightly lower in older adults associated with potential nutritional deficiency. Values are slightly lower in older adults.Note: See “Complete Blood Count, RBC Count” study for more detailed information.

Red Blood Cell Indices
AgeMCV (fl)MCH (pg/cell)MCHC (g/dL)RDWCVRDWSD
Cord blood107–11935–3931–3514.9–18.751–66
0–1 wk104–11629–4524–3614.9–18.751–66
2–3 wk95–11726–3826–3414.9–18.751–66
1–2 mo81–12525–3726–3414.9–18.744–55
3–11 mo78–11022–3426–3414.9–18.735–46
1–5 yr74–9424–3230–3411.6–14.835–42
6–8 yr73–9324–3232–3611.6–14.835–42
9–14 yr74–9425–3332–3611.6–14.837–44
15 yr–adult
Older adult
MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration;MCV = mean corpuscular volume; RDWCV = coefficient of variation in RBC distribution width index;RDWSD = standard deviation in RBC distribution width index.Note: See “Complete Blood Count, RBC Indices” study for more detailed information.

Red Blood Cell Morphology
MorphologyWithin Normal Limits1+2+3+4+
Anisocytosis0–55–1010–2020–50Greater than 50
Macrocytes0–55–1010–2020–50Greater than 50
Microcytes0–55–1010–2020–50Greater than 50
Poikilocytes0–23–1010–2020–50Greater than 50
Burr cells0–23–1010–2020–50Greater than 50
AcanthocytesLess than 12–55–1010–20Greater than 20
SchistocytesLess than 12–55–1010–20Greater than 20
Dacryocytes (teardrop cells)0–22–55–1010–20Greater than 20
Codocytes (target cells)0–22–1010–2020–50Greater than 50
Spherocytes0–22–1010–2020–50Greater than 50
Ovalocytes0–22–1010–2020–50Greater than 50
Stomatocytes0–22–1010–2020–50Greater than 50
Drepanocytes (sickle cells)AbsentReported as present or absent
Helmet cellsAbsentReported as present or absent
AgglutinationAbsentReported as present or absent
RouleauxAbsentReported as present or absent
Hemoglobin Content
Hypochromia0–23–1010–5050–75Greater than 75
AdultLess than 12–55–1010–20Greater than 20
Newborn1–67–1515–2020–50Greater than 50
Note: See “Complete Blood Count, RBC Morphology and Inclusions” study for more detailed information.

Red Blood Cell Inclusions
InclusionsWithin Normal Limits1+2+3+4+
Cabot’s ringsAbsentReported as present or absent
Basophilic stippling0–11–55–1010–20Greater than 20
Howell-Jolly bodiesAbsent1–23–55–10Greater than 10
Heinz bodiesAbsentReported as present or absent
Hemoglobin C crystalsAbsentReported as present or absent
Pappenheimer bodiesAbsentReported as present or absent
Intracellular parasites (e.g., Plasmodium, Babesia, trypanosomes)AbsentReported as present or absent
Note: See “Complete Blood Count, RBC Morphology and Inclusions” study for more detailed information.

Platelet Count
AgeConventional UnitsSI Units (Conventional Units × 1)MPV (fl)IPF (%)
Birth150–450 × 103/microL150–450 × 109/L7.1–10.21.1–7.1
Child/Adult/Older adult140–400 × 103/microL140–400 × 109/L7.1–10.21.1–7.1
Note: See “Complete Blood Count, Platelet Count” study for more detailed information. Platelet counts may decrease slightly with age.

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