i bc27f85be50b71b1 (117 page)

size, shape, and Hgb distribution. WBCs are examined for proportion

and the presence of immature cells. Finally, Pits are examined for

number and shape." Peripheral blood smear results are correlated

with the other laboratory tests to diagnose hematologic disease.

Coagulation Profile

Coagulation tests assess the blood's ability to clot. The tests used to

determine c10rting are prothrombin time (PT) and partial thromboplastin time (PTT). An adjunct to the measurement of PT is the International Normalized Ratio (INR). The INR was created to ensure reliable and consistent measurement of coagulation levels among all

Table 6-8. Erythrocyte Indices: V:t1ues and inrerpretation·

Test

Description

Value

Interpretation

Mean corpuscular volume

Mean size of a single

80-100 pgJ

Increased by macrocytic, folic acid, or vitamin

(MCV) (Het x 101RBC)

RBC in a pi of

BI2 deficiency anemias; liver disease; and

blood

recent alcohol use.

Decreased by microcytic, iron-deficiency, and

hypochromic anemias; thalassemia; and lead

pOisoning.

Mean corpuscular hemoglobin

Amount of Hgb in one

26-34 pglcell

Increased by macrocytic anemia.

(MCH) (Hgb x 101RBC)

RBC

Decreased by microcytic anemia.

Low mean corpuscular hemoglobin indicates

<

Hgb deficiency.

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Mean corpuscular hemoglobin

Proportion of eaeh

3 1-37 gldl

Increased by spherocytosis (small round

n

c

concentration (MCHC)

RBC occupied by

RBC).

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(HgblHet x 100)

Hgb

Decreased by microcytic, hypochromic, and

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iron-deficiency anemias and thalassemia.

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Het = hematocrit; Hgb = hemoglobin; RBC = red blood cell.

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Z

"'Lab values vary among laboratories.

o

Sources: Adapted from RJ Elin. LaboratOry Reference Intervals and Values. In L Goldman, JC Bennett (cds). Cecil Textbook of Medicine,

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Vol. 2 (21 st cd). Philadelphia: Saunders, 2000;2305j and E Matassarin-Jacobs. Assessment of Clients with Hemarologic Disorders. In JM

Black. E Marassarin·Jacobs (eds), Medical-Surgical Nursing Clinical Management for Continuity of Care (5th cd). Philadelphia: Saun

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ders, 1997;1466.

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384 ACUTE CARE HANDBOOK FOR PHYSICAL THERAI'ISTS

laboratories. The INR is the ratio of the patient's PT to the standard

PT of the laboratory, raised by an exponent (the sensitivity index of

the reagent) provided by the manufacturer.'2 Table 6·9 summarizes

PT/INR and PTT.

Clinical Tip

When confirming an order for physical therapy in the phy·

sician's orders, the therapist must be sure to differentiate

between the order for physical therapy and the blood tesr

(i.e., rhe abbreviarions for both physical therapy and prothrombin time are PT).

Pathophysiology

This section is divided into a discussion of vascular and hematologic

disorders.

Vasclilar Disorders

Vascular disorders are classified as arterial, venous, or combined arterial and venous disorders. Clinical findings differ berween anerial and venous disorders, as described in Table 6-10.

Arterial Disorders

Atherosclerosis

Atherosclerosis is a diffuse and slowly progressive process characterized by areas of hemorrhage and the cellular proliferation of mono·

cytes, smooth muscle, connective tissue, and lipids." The development

of atherosclerosis begins early in life with risk factors that include the

followingM.Il-IS:

.. Arteriosclerosis is a general term used to describe any wall thickening or

hardening in the arteries. The term atheroma is applied to plaque formation

with farty material in the vessel wall.

Table 6-9. Coagulation Profile

Test

Description

Value" (sees)

J ndicationlInterpreta tion

PrOthrombin rime!

Examines the extrinsic

PT 11-15

Used to assess the adequacy of warfarin

international

and common dor

(Coumadin) therapy or ro screen for

normalized ratio

ring facmrs I, II, V,

bleeding disorders

(PT/INR)

VII, and X

Increased: Coumarin therapy, liver diseases,

bile duct obstruction, diarrhea, salicylate

intoxication, Ole, hereditary facro[ deficiency, alcohol use, or drug interaction

Decreased: Diet high in fat or leafy vegetables, or drug interaction

Partial thromboplastin

Examines the intrinsic

PIT 60-70

Used to assess the adequacy of heparin therrime (PIT) (acriand common clot

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APIT 30--40

apy and ro screen for bleeding disorders

vared PIT [APIT] is

ting factors I, II, V,

Increased: Heparin or coumarin therapy,

i:

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a rapid version of

VIII, IX, X, XI

liver disease, vitamin K or congenital dot

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-<

PIT)

ting factor deficiency, DrC

Decreased: Extensive cancer, early DIC

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ole

8

= disseminated imr:lVascular coagulopathy.

·Values for prothrombin rime (PT) and PlT vary between laborarories.

:t

m

Source: Dara from KD Pagana, TJ Pagana. Blood Srudies. Mosby's Manual of Diagnostic and Laborarory Tests. St. Louis: Mosby, 1998.

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