TEST

NORMAL RANGE

DESCRIPTION

INDICATIONS/COMMENTS

Complete blood count (CBC)

General survey of bone marrowfunction; evaluates all three celllines (WBCs, RBCs, platelets)

Important to note changes overtime; many hematologic conditionsshow changes in CBClong before patient becomessymptomatic

Red blood cells (RBCs)

M: 4.7–6.1 Χ 106F: 4.2–5.4 Χ 10 to the power of 6

Carries hemoglobin; survival time,120 days

Hemoglobin (Hgb)

M: 13.5–17.5 g/dLF: 11.5–15.5 g/dL

Delivers O2 through circulationto body tissues and returns CO2from tissues to lungsIndicates relative proportions of

Decreased in anemia; increased inpolycythemia

Hematocrit (Hct)

M: 40–52%F: 36–48%

Indicates relative proportions ofplasma and RBCs (volume ofRBCs/L whole blood)

Usually three times the Hgb

Mean corpuscular volume (MCV)

81–96 ?m3

Indicates size of RBCs; very usefulin differentiating types of anemia

If <80, cells are microcytic; if >100 cells re macrocytic

Mean corpuscular volume hemoglobin concentration (MCHC)

33–36 g/dL

Average concentration of Hgb inRBCs; independent of cell size

Left shift: bone marrow ? productionof WBCs; more immatureforms released into the bloodstream

Red cell distribution width (RDW)

11–14.5%

Measures degree of variation in sizeof RBCs

Increased in liver disease, disseminatedintravascular coagulation(DIC), obstructive biliary disease,clotting factor depletion, warfarin(Coumadin) use

Reticulocyte count

0.5–1.5%

Measure of marrow production of

erythrocytes; 1% of RBC mass is

produced daily (to replace the 1%

of old cells that die)

Indicates marrow’s response to anemia

(when anemia is present,

reticulocyte level should rise)

Platelets

150,000–400,000/mm3

Total number of platelets in circulation;

average life span, 7–10 days

Thrombocytopenia: < 20,000/mm3,

serious; < 10,000/mm3, potentially

life-threatening

White blood cells (WBCs)

Differential

4,500–11,000/mm3

Percentages of various types of

WBCs

Total WBC count

% of cell type Χ total WBC =

absolute number of that cell type

Prothrombin time (PT)

Varies (compare with control),

11–12.5 sec

Measure time elapsed until clot

forms; measures extrinsic and

common pathways

Increased in liver disease, disseminated

intravascular coagulation

(DIC), obstructive biliary disease,

clotting factor depletion, warfarin

(Coumadin) use

International normalized

ratio (INR)

1.0

Standard warfarin (Coumadin)

treatment, 2.0–3.0 INR;

high-dose warfarin (Coumadin)

treatment, 3.0–4.5 INR

A standard method of measuring

PT independent of the thromboplastin

reagent used in the test;

calculated by dividing the PT

result by the mean normal PT

Increased with anticoagulant excess

and conditions that cause increased

PT; decreased with insufficient

anticoagulant and

conditions that cause decreased PT

Partial thromboplastin time

(PTT)

Varies (compare with control):

25–35 sec

Surface active agent added to

plasma; measures time elapsed

until clot forms; measures intrinsic

and common pathways

Increased in clotting factor depletion,

DIC, liver disease, biliary

obstruction, circulating anticoagulants

(heparin)

Thrombin time (TT)

Varies (compare with control),

8–11 sec

Tests conversion of fibrinogen to

fibrin

Time to clot is inversely proportional

to fibrinogen level

Fibrinogen

170–340 mg/100 mL

Measurement of fibrinogen concentration

within plasma available

for conversion to fibrin clot

Decreased in bleeding disorders,

pregnancy, malignancy, inflammatory

disease)

D-dimer

0–0.5μg/mL

Measures the amount of fragments

of fibrin when it is lysed (broken

down); useful for distinguishing

fibrinolysis from fibrinogenolysis

Increased with fibrinolytic activity,

rheumatoid arthritis, ovarian

cancer (with increased CA 125)

Fibrin degradation products

(FDP)

<10 μg/mL

Byproduct of fibrinolysis

>40 μg/mL indicates DIC

Neutrophils

40–75% (2,500–7,500/mm3)

Essential in preventing/limiting

bacterial infection; average life

span: 2–4 hr

If >8,000: infection, some inflammatory

states, stress, steroids,

other drugs, myeloproliferative

disease. Absolute neutrophil count (ANC)

<500: increased risk for infection;

ANC <100: infection certain

(if neutropenia persists)

Lymphocytes

20–50% (1,500–5,500/mm3)

Integral component of immune system

<1,500: lymphopenia; >4,000:lymphocytosis; increased in convalescentphase after bacterial orviral infection, lymphoproliferativedisease

Monocytes

1–10% (100–800/mm3)

Enter tissue as macrophages; phagocytosis

Increased in acute and chronic infection,inflammation, somemyeloproliferative disorders,chronic myelomonocyticleukemia (CMML)

Eosinophils

0–6% (0–440/mm3)

Involved in allergic reactions (neutralizes histamine); digest foreign proteins

Increased in allergic states, medications,parasites, chronic myeloidleukemia (CML), metastatic/necrotic tumors

Basophils

0–2% (0–200/mm3)

Contain histamine; integral part of hypersensitivity reactions

Increase is very rare (CML)