anemia of chronic inflammation. A large MCV indicates a macrocytic cell, which can

be caused by a vitamin B12 or folic acid deficiency. Underlying disease states (e.g.,

habitual alcohol ingestion, chronic liver disease, anorexia nervosa, hypothyroidism,

reticulocytosis, and hematologic disorders) may also present with an elevated MCV

secondary to deficiencies in these vitamins.

34 The MCV can be normal in a patient

with a “mixed” (microcytic and macrocytic) anemia. Note that a direct assessment of

a blood smear by a microscopic examination is the gold standard for confirming RBC

size.

MEAN CELL HEMOGLOBIN

The MCHC is a more reliable index of RBC Hgb than MCH. MCH measures the

weight of Hgb in the RBCs in a sample and MCHC measures concentration of the

RBCs contained within a sample. In normochromic anemias, changes in the size of

RBCs (MCV) are associated with corresponding changes in the weight of Hgb

(MCH), but the concentration of Hgb (MCHC) remains normal. Changes in the Hgb

content of RBCs alter the color of these cells. Thus, hypochromic refers to a decrease

in RBC Hgb, reflected by reduced MCHC, and may indicate iron-deficiency anemia.

Conversely, hyperchromic RBCs have an elevated MCHC because of the presence of

greater amounts of Hgb. Hyperchromic cells are not commonly encountered.

Reticulocytes

Adults—Reference Range: 0.5%–1.5%of RBCs or 0.005–0.015

Reticulocytes are young, immature erythrocytes and typically comprise about 1%

of the RBCs. The reticulocyte count measures the percentage of these new cells in the

circulating blood. An increase in the number of reticulocytes implies an increased

number of erythrocytes are being released into the blood in response to a stimulus.

Reticulocyte count is a good indicator of bone marrow activity because it represents

a recent production. Because erythrocytes regenerate rapidly, reticulocytosis can be

noted within 3 to 5 days after hemolysis or after a hemorrhagic episode. Appropriate

treatment of anemias caused by iron, vitamin B12

, or folic acid deficiencies should

result in an increased reticulocyte count. Caution must be exercised in the

interpretation of reticulocyte counts. Changes in the number of RBCs will result in

proportional changes in the reticulocyte count because the latter is reported as a

percentage of the number of RBCs.

Erythrocyte Sedimentation Rate

Reference Range: 0–30 mm/hour

The ESR is the rate (expressed in mm/hour) at which erythrocytes settle to the

bottom of a test tube through the forces of gravity and in response to fibrinogen levels

in the blood. The ESR is a nonspecific value and may be increased abnormally in

acute and chronic inflammatory processes, acute and chronic infections, neoplasms,

infarction, tissue necrosis, rheumatoid-collagen disease, dysproteinemias, nephritis,

and pregnancy. However, ESR can also be affected by changes not related to the

inflammation (e.g., change in erythrocyte size, shape, or number). Laboratory

technique can also affect the sedimentation rate substantially. Because many factors

can enhance the settling rate of RBCs, moderate to marked elevation of the ESR

merely indicates an inflammatory component to a disease state. An increased ESR in

the setting of a normal physical examination is usually transient and is rarely the

harbinger of serious occult disease.

35

White Blood Cells

Reference Range: 3.8–9.8 × 10

3

/µL or 3.8–9.8 × 10

9

/L

Leukocytes or WBCs comprise five different types of cells. Neutrophils are the

most abundant of the circulating WBCs, followed in order of frequency by

lymphocytes, monocytes, eosinophils, and basophils. The neutrophils, eosinophils,

basophils, and monocytes are formed from stem cells in the bone marrow.

Lymphocytes are formed primarily in the lymph nodes, thymus, spleen, and, to a

lesser extent, bone marrow (Fig. 2-2). Each WBC type has unique function, and it is

best to consider them independently rather than collectively as “leukocytes.”

36

Ultimately, all WBCs contribute to host defense mechanisms.

NEUTROPHILS

Reference Range: 40%–70%of WBC

The terms polys, segs, polymorphonuclear neutrophils, and granulocytes are

synonymous with the term neutrophil in clinical practice. The number of neutrophils

is commonly increased during bacterial or fungal infections, because these cells are

essential in killing invading microorganisms. Whereas the bone marrow increases

production of new leukocytes, there is also an increase in the number of circulating

immature neutrophils (e.g., bands); this phenomenon is commonly referred to as a

“left shift,” which suggests acute bacterial infection.

However, neutrophils are also important in the pathogenesis of tissue damage in

some noninfectious diseases, such as rheumatoid arthritis, inflammatory bowel

disease, asthma, MI, or gout.

37

Increased neutrophils or neutrophilia can also be

encountered during metabolic toxic states (e.g., diabetic ketoacidosis, uremia, and

eclampsia) and during physiologic response to stress (e.g., physical exercise and

childbirth). Drugs (e.g., epinephrine and corticosteroids) can also cause significant

neutrophilia, primarily caused by demargination from blood vessel walls.

Agranulocytosis and Absolute Neutrophil Count

The condition involving decreased neutrophils, or neutropenia, is defined as a

neutrophil count of <2,000 cells/μL; agranulocytosis refers to severe neutropenia.

The most common causes of neutropenia are metastatic carcinoma, lymphoma, and

chemotherapeutic agents. The degree of neutropenia is often expressed by the

absolute neutrophil count (ANC). The ANC is defined as the total number of

granulocytes (polymorphonuclear leukocytes and band forms) present in the

circulating pool of WBCs and can be calculated as WBC × (% neutrophils + %

bands)/100. Generally, the risk of infection is low when the ANC exceeds 1,000/μL;

however, the risk of infection increases significantly when the ANC is less than

500/μL. The risk of developing bacteremia is increased further as the ANC

decreases to less than 100/μL, a condition commonly referred to as “profound

neutropenia.” The most common causes of neutropenia are metastatic carcinoma,

lymphoma, and chemotherapeutic agents. The reader is referred to Chapter 75,

Prevention and Treatment of Infections in Neutropenic Patients, for a more detailed

explanation.

LYMPHOCYTES

Reference Range: 22%–44%of WBC

Lymphocytes constitute the second most common WBC in circulating blood. These

leukocytes respond to foreign antigens by initiating the immune defense system. The

vast majority of lymphocytes are located in the spleen, lymph nodes, and other

organized lymphatic tissue. The lymphocytes circulating in blood represent less than

5% of the total amount in the body.

There are two major types of lymphocytes. T lymphocytes (thymic dependent)

participate in cell-mediated immune responses, and B lymphocytes (bone marrow

derived) are responsible for humoral antibody responses. Therefore, diseases

affecting lymphocytes primarily manifest themselves as immune deficiency disorders

that render the patient unable to defend against normal pathogens (see Chapter 76,

Pharmacotherapy of Human Immunodeficiency Virus Infection) or as autoimmune

diseases in which immune responses are directed against the body’s own cells.

36

p. 33

p. 34

Increased numbers of lymphocytes on a white count differential sometimes

accompany lymphoma (see Chapter 96, Adult Hematologic Malignancies) and viral

infections. A relative lymphocytosis is sometimes encountered when the total

lymphocytes have remained constant despite a decline in the total neutrophils.

MONOCYTES

Reference Range: 4%–11%of WBC

Monocytes are formed in the bone marrow and are the precursors to macrophages

and antigen-presenting cells (dendritic cells), which are found in the body’s tissues.

38

Macrophages and dendritic cells are phagocytic cells that engulf foreign antigens or

dead or dying cells. Dendritic cells also present fragments of antigens to T and B

lymphocytes. Monocytosis may be observed in mononucleosis, subacute bacterial

endocarditis, malaria, and tuberculosis, as well as during the recovery phase of some

infections.

EOSINOPHILS

Reference Range: 0%–8%of WBC

Because eosinophils have surface receptors that bind IgG and IgE, they can modify

reactions associated with IgG- and IgE-mediated degranulation of mast cells.

Primary lysosomal granules, small dense granules, and specific or secondary

granules are the three types of granules found within eosinophils. The latter granules

account for most of the biologic activity of eosinophils and are toxic to parasites,

tumor cells, and some epithelial cells.

39

Eosinophils have phagocytic activity, catalyze the oxidation of many substances,

facilitate killing of microorganisms, initiate mast cell secretion, protect against

various parasites, and play some role in host defense. Eosinophilia is probably most

commonly associated with allergic reactions to drugs, allergic disorders (e.g., hay

fever, asthma, and eczema), invasive parasitic infections (e.g., hookworm,

schistosomiasis, and trichinosis), collagen vascular diseases (e.g., rheumatoid

arthritis, eosinophilic fasciitis, and eosinophilic-myalgia syndrome), and

malignancies (e.g., Hodgkin lymphoma).

40–42

BASOPHILS

Reference Range: 0%–3%of WBC

During infection or inflammation, basophils leave the blood and mobilize as mast

cells to the affected site and release granules. These granules contain histamine,

serotonin, prostaglandins, and leukotrienes. Degranulation results in an increased

blood flow to the site and may compound inflammatory processes. An increase in

basophils commonly accompanies allergic and anaphylactic responses, chronic

myeloid leukemia, myelofibrosis, and polycythemia vera. A decrease in the number

of basophils is generally not readily apparent because of the small number of these

cells in the blood.

36

CASE 2-5

QUESTION 1: L.H., a 50-year-old female, is hospitalized with a sustained high fever of 39.2°C and severe

back pain. The results of the CBC and leukocyte differential are as follows:

Total WBC count: 21,000/μL

Neutrophils: 74%

Bands: 6%

Lymphocytes: 14.6%

Monocytes: 8%

Eosinophils: 1%

Basophils: 0%

Imaging and other blood work was ordered. L.H. is diagnosed with an abscess in her lower back and

Staphylococcus aureus bacteremia. How is L.H.’s laboratory report consistent with a systemic bacterial

infection?

WBCs are the host’s chief defense system, and the neutrophil is the main

component of that system. During bacterial infections, the leukocyte count and the

neutrophils are generally increased, and a left shift (increase in bands) may be

noticeable. The percentage of other types of WBCs is decreased proportionately

because the number of neutrophils is increased.

As the infection progresses, the percentage of band cells may decrease as a result

of an increase in the number of neutrophils that have a longer half-life. This decrease

in bands does not necessarily indicate improvement. A decrease in the percentage of

neutrophils with a decrease in the total WBC count is characteristic of effective

antibiotic therapy.

CASE 2-5, QUESTION 2: The S. aureus causing L.H.’s bacteremia is found to be methicillin sensitive, and

she is started on oxacillin 2 million units IV q 4 hour for treatment. After about a week of therapy, L.H.

develops a fine red rash all over her body, mild lymphadenopathy, low-grade fever, and generalized swelling.

The CBC shows a total WBC count of 8,600/μL with 11% eosinophils. What is the significance of this

eosinophil count?

In the clinical setting, absolute leukocyte counts may be used in conjunction with

normal reference values. Absolute counts are calculated by multiplying the

percentage of each individual cell by the total leukocyte count. Eosinophils are

usually increased in allergic reactions; therefore, a drug-induced hypersensitivity

reaction is a strong probability in L.H., with an absolute count of 946 eosinophils/μL

(i.e., 11% of 8,600 leukocytes). The clinician should be suspicious of an allergic

drug reaction when absolute eosinophil counts exceed 300 cells/μL. Eosinophils may

increase before, after, or concurrent with other evidence of allergy (e.g., rash).

Eosinophilia without evidence of allergy is not sufficient cause to discontinue a

suspected medication unless the eosinophilia is significant (i.e., >2,000 cells/μL). In

addition, the absence of eosinophilia certainly does not rule out an allergic diagnosis

in a patient exhibiting clear clinical manifestations of an apparent allergic reaction.

Thrombocytes

Reference Range: 150–450 × 10

3

/µL or 150–450 × 10

9

/L

Thrombocytes, commonly referred to as platelets, are tiny fragments of cells that

assist with normal blood clotting. Platelet testing is included as part of a CBC and is

often ordered along with other coagulation studies to evaluate bleeding and/or

clotting disorders. Decreased platelet counts or thrombocytopenia may lead to

petechiae, ecchymosis, and spontaneous hemorrhage.

Causes include decreased platelet production, accelerated destruction, loss from

excessive bleeding or trauma, dilution of blood samples secondary to blood

transfusion, sequestration secondary to hypersplenism, disseminated intravascular

coagulation, infection, or systemic lupus erythematosus. Malignancy, rheumatoid

arthritis, iron-deficiency anemia, polycythemia vera, and postsplenectomy syndromes

are the most common causes of elevated platelet counts or thrombocytosis.

Coagulation Studies

The control of bleeding depends on the formation of a platelet plug and the formation

of a stable fibrin clot. The formation of this clot depends on the complex interactions

of plasma proteins and clotting factors. The prothrombin time (PT), international

normalized ratio (INR), and activated partial thromboplastin time (aPTT) are used to

diagnose coagulation abnormalities or to monitor the effectiveness of patients

receiving anticoagulation therapy. When used to assess drug therapy, achieving a

value outside the reference range is in fact a therapeutically desirable outcome.

p. 34

p. 35

ACTIVATED PARTIAL THROMBOPLASTIN TIME

Reference Range: 22–37 seconds

aPTT measures the time it takes the body to form a clot. aPTT depends on the

activity of factors VIII, IX, XI, and XII (intrinsic pathway) and the factors involved in

the final common pathway of the clotting cascade (II, X, and V). aPTT is commonly

measured to detect bleeding disorders and coagulation deficiencies and monitor

unfractionated heparin therapy. The reader is referred to Chapter 11, Thrombosis, for

more detailed information regarding the use of coagulation parameters in treating and

monitoring thrombotic disorders.

PROTHROMBIN TIME

Reference Range: 10–13 seconds

Prothrombin is synthesized in the liver and is converted to thrombin during the

blood clotting process. Thrombin formation is the critical event in the hemostatic

process because thrombin creates fibrin monomers that ultimately assemble into a

clot and stimulates platelet activation. The PT test evaluates the integrity of the

extrinsic and common pathways and directly measures the activity of clotting factors

VII and X, prothrombin (factor II), and fibrinogen. Automated laboratory instruments

measure PT by recording the time required for the blood to clot after a reagent (i.e.,

tissue thromboplastin) has been added to the patient’s blood sample.

INTERNATIONAL NORMALIZED RATIO

Because different labs use different reagents, the PT results obtained from one

reagent cannot be reliably compared with another reagent. Therefore, the INR is used

as a standard unit to report the result of a PT test. The INR is the recommended

method to monitor both the initiation and maintenance of anticoagulant therapy, most

notably warfarin. Individuals who have normal blood clotting and are not on

anticoagulation therapy should have an INR of 1. For patients on anticoagulation

therapy, the target INR (i.e., therapeutic range) is usually between 2.0 and 4.0

depending on the indication and other patient-specific factors. Outside of the

therapeutic range, the higher the INR, the higher the likelihood of bleeding because

the blood is taking longer to clot. Conversely, if the INR is lower, there is an

increased risk of developing a clot. Many factors including medications, diet, alcohol

intake, and certain medical conditions can influence the INR.

The INR is calculated using Equation 2-12, where the prothrombin ratio (PTR) is

the ratio between the patient’s PT and the laboratory’s control PT, and the ISI is the

international sensitivity index. Commercial manufacturers quantify the ISI for the

specific thromboplastin reagent used in each lot and report this information in the

product package insert:

URINALYSIS

A standard urinalysis includes physical, chemical, and microscopic evaluations to

assist with diagnosis of various urologic conditions. It begins with simple

observation of the color and the gross general appearance of the urine specimen. The

urine pH and specific gravity are then recorded. Formed elements in the urine are

examined microscopically, and the urine is searched routinely for pathologically

significant substances that are normally not present (e.g., glucose, blood, ketones, and

bile pigments). Urine specimens should be evaluated quickly after collection to

minimize unreliable results. The reader is referred to Chapter 71, Urinary Tract

Infections, for a more detailed description of the use of urinalysis in the detection and

monitoring of urinary tract infections (UTIs).

Gross Appearance of the Specimen

The concentrated, first-morning urine specimen is usually analyzed to eliminate

effects of undue dilution as a result of water intake. The color should be slightly

yellow, depending on the degree of dilution, and the appearance should be clear. The

appearance of the urine may reveal clouds of crystals, bilirubin, blood, porphyrins,

proteins, food or drug colorings, or melanin. Discolored urine is abnormal. A red

coloration of the urine may be imparted by blood, porphyria, or ingestion of

phenolphthalein. A brown urine color may be caused by the acid hematin of blood or

from melanin pigments. Excessive excretion of urobilinogen or the effects of drugs

such as rifampin or phenazopyridine may cause a dark orange urine color. A blue to

blue-green color of the urine may result from the systemic administration of

methylene blue.

Specimen pH

When freshly produced, urinary pH can range from 4.5 to 8 but is mostly acidic

because of metabolic activity. Alkaline urine may indicate an aged specimen,

systemic alkalosis, failure of renal acidifying mechanisms, or infection in the urinary

tract.

Specific Gravity

Urinary specific gravity provides information regarding a patient’s hydration status.

A normal morning urine specimen should have a specific gravity of 1.003 to 1.030.

The upper end of this range is close to the maximal concentrating ability of the

kidney. A value of 1.010 or less supports relative hydration, whereas a value greater

than 1.020 indicates relative dehydration.

Protein

Proteinuria is a classic sign of renal injury. If proteinuria is found during the

evaluation of a patient with a nonrenal illness, it suggests that the disease may also

involve the kidneys (i.e., hypertension and diabetes).

43 A healthy adult generally

excretes 30 to 130 mg/day of protein into the urine.

Protein in a urine sample is generally tested qualitatively on a random urine

sample by a dipstick method and is usually reported on a scale of 0 (<30 mg/dL), 1+

(30–100 mg/dL), 2+ (100–300 mg/dL), 3+ (300–1,000 mg/dL), and 4+ (>1,000

mg/dL). A positive qualitative test for urine protein should be repeated after a few

days because transient proteinuria can accompany various physiologic and

pathologic states, even when kidney function is normal. Therefore, patients with

CHF, seizures, or febrile illnesses and normal renal function need not undergo

invasive renal function tests if the proteinuria is modest and likely to be transient.

Another qualitative evaluation of proteinuria can be performed in about 2 weeks to

confirm the diagnosis of transient proteinuria.

44

If subsequent qualitative test results

are positive, a 24-hour urine sample should be collected to quantitatively test for

protein and creatinine (see Creatinine Clearance section). In patients with a normal

24-hour urinary protein concentration, previous positive qualitative test results

probably represent either false-positive results or a transient phenomenon.

42 A

laboratory parameter being used with increased frequency to assess proteinuria is the

urine albumin to urine creatinine ratio (UACR). This measurement tends to be less

influenced by fluctuations in urine concentration and may offer a more reliable

indication of proteinuria. UACR values are typically less than 30 mg/g; patients with

values between 30 and 300 mg/g are considered to have microalbuminuria, and

UACR values greater than 300 mg/g indicate macroalbuminemia.

p. 35

p. 36

MICROSCOPIC EXAMINATION

The urine sediment is examined for RBCs, WBCs, casts, yeast, crystals, and

epithelial cells.

RBCs should be absent in normal urine, although fewer than 4 to 6 RBCs per highpower field (HPF) would still be considered in the normal range. Bleeding or

clotting disorders, some collagen diseases, and various bladder, urethral, and

prostatic conditions may cause microscopic hematuria. In women, vaginal blood

occasionally contaminates the urine specimen, but the presence of numerous

squamous epithelial cells should be sufficient to alert clinicians to this artifact.

WBCs should be virtually absent in normal urine, although up to 5 WBCs/HPF

would still be in the reference range. The presence of WBCs in the urine (pyuria)

usually suggests an acute infection in the urinary tract. Some noninfectious

inflammatory diseases of the kidney, ureter, or bladder may also contribute WBCs to

the urine sediment.

Casts may be used to identify the location of disease in the genitourinary tract.

Casts are composed of proteinaceous or fatty material that outlines the shape of the

renal tubules where they are deposited. The presence of casts must be interpreted in

light of other factors related to the kidney and its function; however, fatty casts, RBC

casts, and WBC casts are always significant. RBC casts usually suggest glomerular

injury, and WBC casts suggest tubular or interstitial injury. Lipid casts with

proteinuria are characteristic findings in patients with nephrotic syndrome or

hypothyroidism.

43 The finding of hyaline casts alone in the presence of proteinuria

suggests a renal origin for the protein. Hyaline or granular casts alone, however, only

suggest some defect in factors that affect cast formation and are therefore difficult to

interpret.

Crystals may originally appear as a cloud in the urine. Their formation is pH

dependent, and they often appear only as the urine cools to room temperature or in

concentrated urine. In acidic urine, crystals may be uric acid or calcium oxalate; in

alkaline urine, they may be phosphates. Crystals per se are not highly significant,

although they may reflect a tendency toward the formation of renal calculi.

CASE 2-6

QUESTION 1: S.T. is a 33-year-old female with type 1 diabetes who presents to the urgent care clinic with a

3-day history of fever, malaise, dysuria, and flank pain. Upon interview, you learn that over the past few days,

S.T. has been unable to keep down any food because of feelings of nausea. Because of this, she has not taken

her insulin for 48 hours. Today, her finger stick blood glucose is 415 mg/dL, and a STAT midstream urinalysis

and Gram stain indicate the following:

pH: 5.2

Appearance: cloudy

Specific gravity: 1.033

Urine protein: 3+

Urine glucose: 4+

Urine ketones: positive

Urine bacteria: 4+

Urine WBC: too numerous to count (TNTC)

Squamous epithelial: few per HPF

Urine nitrite: positive

Gram stain: numerous Gram-negative rods

What objective data from the urinalysis indicate a UTI?

The cloudy appearance of S.T.’s urine indicates the presence of bacteria, protein,

and WBCs, which is supported by the urinalysis results. The lack of a significant

amount of squamous epithelial cells, the presence of a significant amount of nitriteproducing bacteria, and the Gram stain indicate a clean-catch urine specimen and a

UTI involving Gram-negative organisms (most likely Escherichia coli that causes a

majority of UTIs).

CASE 2-6, QUESTION 2: What objective data from the urinalysis indicate uncontrolled diabetes?

Glucose is normally filtered in the glomerulus and a majority is reabsorbed in the

proximal tubule of the kidney. S.T.’s glycosuria (4+ glucose) and fingerstick of 415

mg/dL indicate the filtered amount of glucose exceeds the capacity for reabsorption

(˜180 mg/dL). Additionally, the presence of positive ketones indicates the body is

utilizing fat, not glucose, for energy. High levels of ketones can predispose S.T. to

dehydration, resulting in diabetic ketoacidosis.

THERAPEUTIC DRUG MONITORING

Many drugs have a wide dosing range that can achieve efficacy with low risk of

toxicity. Drugs that have a narrow dosing range with high risk of toxicity (narrow

therapeutic index) often have their blood levels monitored. Results from therapeutic

drug monitoring assist clinicians with appropriate dosing adjustments to prevent

toxicity and achieve appropriate clinical outcomes. Pharmacokinetic parameters as

well as drug interactions may significantly impact the laboratory results and must be

integrated into the clinical assessment of the data. Similarly, for certain drugs and

drug classes, there are recommended laboratory tests that should be performed to

monitor their potential adverse effects on organ systems. Ideally, blood level

monitoring should occur after the drug has reached steady state and at a consistent

time within the dosing interval.

PATIENT-DIRECTED MONITORING AND

TESTING

Often patient-directed self-monitoring is an essential component to successful

management of certain disease states such as blood pressure monitoring for

hypertension and blood glucose monitoring for diabetes mellitus. When used

appropriately, data obtained from these monitoring devices can be used by health

care providers and consumers to initiate or modify therapies accordingly.

Additional laboratory, self-monitoring tests or devices are also available for

consumers to purchase for independent testing or screening purposes at home. Some

products provide an immediate result, whereas others require submitting a completed

kit to a laboratory for analysis. Samples may be obtained from various sources,

including urine, blood, saliva, stool, or hair samples. The incidence of consumers

using these products has significantly increased and likely will continue to climb

because of increased access via the Internet as well as additional tests becoming

available.

In the United States, some, but not all, patient-directed tests have been approved

by the US Food and Drug Administration (FDA). A current listing of approved

products is available through the FDA’s Office of In Vitro Diagnostic Device

Evaluation and Safety (OIVD) and can be accessed online at

http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnosticsConsumers should be cautioned about the accuracy of tests that have not been

approved and the validity of all test results, especially for diagnostic purposes,

p. 36

p. 37

because many factors can impact or interfere with the sensitivity (probability of

obtaining a positive result when sample is truly positive) and specificity (probability

of obtaining a negative result when the sample is truly negative). Follow-up

assessment with a health care provider should be encouraged to confirm or refute

patient-directed test results.

KEY REFERENCES AND WEBSITES

A full list of references for this chapter can be found at

http://thepoint.lww.com/AT11e. Below are the key references and websites for this

chapter, with the corresponding reference number in this chapter found in parentheses

after the reference.

Key References

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Drug Information, LLC. Updated March 24, 2015. (2)

Kratz A et al, eds. Laboratory reference values. N EnglJ Med. 2004;351: 1548–1563. (1)

Lee M. Basic Skills in Interpreting Laboratory Data. 5th ed. Bethesda, MD: American Society of Health-System

Pharmacists; 2013. (3)

Key Websites

Mayo Medical Laboratories Mobile App. http://www.mayomedicallaboratories.com/mobile-apps/

Merck Manual. http://www.merckmanuals.com/professional/appendixes/normal-laboratoryvalues/normal-laboratory-values

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Lee M. Basic Skills in Interpreting Laboratory Data. 5th ed. Bethesda, MD: American Society of Health-System

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