Download Blood Basics and Testing - Alberta Association of Optometrists

Lab Testing: The Basics
Blair Lonsberry, MS, OD, MEd., FAAO
Professor of Optometry
Pacific University College of Optometry
[email protected]
.
Case History
• 49 WF presents with a complaint of
blurry/fluctuating vision at distance and near
• PMHx:
– Hypertension 15 years
– Review of Systems:
• Joint pain
• Seasonal allergies
• Ocular: dryness, redness, burning, blurriness
• POHx: no surgeries or trauma reported
• Meds: HCTZ
Entrance Skills
• VA (corrected):
– +1.00 – 0.50 x 180 20/25
– +1.00 – 0.50 x 180 20/25
• All other entrance skills unremarkable
• Refraction:
– +1.25 – 0.50 x 180 20/25
– +1.25- 0.75 x 180 20/25
• Patient notes vision “still not quite right” and
“fluctuating”
Rheumatoid Arthritis
• Collagen vascular disorders:
– most common form of
inflammatory joint disease
– lead to most common form
of physical disability in the
US
• Average onset between 3550
• familial predisposition
• 3x more females
• Predominately Caucasian
Rheumatoid Arthritis
• Rheumatoid Arthritis (RA) is not a benign
disease.
• RA is associated with decreased life
expectancy.
– The risk of cardiovascular mortality is twice that of
the general population.
• Affecting approximately 1% of the adult
population, RA is associated with considerable
disability.
Rheumatoid Arthritis
Epidemiology-Systemic
• Bilateral predilection for
peripheral joints
extending towards trunk
– hands-elbows-ultimately
shoulders
• Chronic inflammation
leads to erosion of bony
surfaces and
cartilaginous destruction
– this leads to joint
deformity and physical
impairment
Other Diagnostic Criteria for RA
Cutaneous
Ocular
Pulmonary
Cardiac
Neurological
Nodules
Sicca
Pleuritis
Pericarditis
Peripheral
neuropathy
Leukopenia
Vasculitis
Episcleritis
Nodules
Atherosclerosis
Cervical
myelopathy
Anemia of chronic
disease
Scleritis
Interstitial
lung disease
Myocardial
infarction
Fibrosis
Hematological
Lymphadenopathy
Osteoarthritis (OA) vs. RA
• Etiology of RA is
inflammatory which
improves with activity
while osteo is mechanical
and worsens with activity
• Infl’n secondary to
mechanical insults in osteo
while no previous insult
required in RA
• Joint cartilage is primary
site of articular
involvement in osteo while
its the bony surfaces of
the joints in RA
Diagnosis
• Many patients have
symptoms that are not
exclusive to RA making
diagnosis difficult
– prodromal systemic
symptoms of malaise, fever,
weight loss, and morning
stiffness
• Lab tests and radiographic
studies are necessary for
initial diagnosis and are
helpful in monitoring
progression
– no one single test is
confirmatory of disease
Criteria for Diagnosis of RA
RA likely if:
– Morning stiffness > 30 minutes
– Painful swelling of 3 or more joints
– Involvement of hands and feet (especially MCP
and MTP joints)
– Duration of 4 or more weeks
– Differential diagnoses include: crystal arthropathy,
psoriatic arthritis, lupus, reactive arthritis,
spondyloarthropathies.
Lab Testing for RA
Tests
Diagnostic Value
Disease Activity Monitoring
ESR or CRP
Indicate only inflammatory process ESR elevated in many but not all
- Very low specificity
active inflammation.
Maybe useful in monitoring disease
activity and response to treatment
RF
RF has a low sensitivity and
specificity for RA.
Seropositive RA has worse
prognosis.
ANA
Positive in severe RA, SLE, or other No value-do not repeat
connective tissue disorders (CTD)
X-rays
Diagnostic erosions rarely seen in
disease of <3 mo’s duration
Joint aspiration
Indicated if infection suspected
No value
Serial x-rays over many years may
show disease progression and indicate
med change
Rheumatoid Factor (RF)
• RF is an autoantibody directed against IgG
• Most common lab testing are latex fixation and
nephelometry
• RF present in 70-90% of patients with RA
– However RF is not specific for RA
– Occurs in a wide range of autoimmune disorders
– Prevalence of positive RF increases with age
• As many as 25% of persons over age of 65 may test positive
– High titer for RF almost always reflects an underlying
disease
Rheumatoid Factor (RF)
• Indication:
– RF should be ordered when there is clinical suspicion of RA
• Interpretation
– Positive test depends on pretest probability of the disease
• If other clinical signs present can provide strong support for
diagnosis of RA
• Keep in mind that the combination of a positive test is not specific
for RA
– Negative test should not completely rule out possibility of
RA
• From 10-30% of patients with long-standing disease are
seronegative
• The sensitivity of the test is lowest when the diagnosis is most
likely to be in doubt
Antibodies to Cyclic Citrullinated
Peptides (anti-CCP)
• Proteins that contain citrulline are the target
of an AB response that is highly specific for RA
• Anti-CCP detected using ELISA
• Associated conditions:
– Appears to be quite specific for RA
• Specificity as high as 97%
– Sensitivity in the range of 70-80% for established
RA and 50% for early-onset
– Has superior specificity and comparable sensitivity
for diagnosis of RA as compared to RF
Antibodies to Cyclic Citrullinated
Peptides (anti-CCP)
Indication:
– Should be ordered when there is a clinical suspicion of
RA
Interpretation:
– Presence provides strong support for the diagnosis of
RA
– In patients with early onset, undifferentiated,
inflammatory arthritis positive results are a strong
predictor of progression to RA and the development of
joint erosion
– Negative test does not exclude possibility of RA
particularly at the time of initial presentation (apprx
50% of patients lack detectable antibodies)
Diagnosis
• Joint x-ray and
radionucleotide evaluation
of suspected inflamed joints
are indicated
Rheumatoid Arthritis: Treatment
• Treatment must be started early to maximize the
benefits of medications and prevent joint damage.
• The use of traditional medications in combination and
the new biologic therapies has revolutionized the
paradigm of RA treatment in recent years.
• The approach to care of patients with RA should be
considered as falling into two groups.
– Early RA (ERA) is defined as patients with symptoms of less
than 3 months duration.
– Patients with established disease who have symptoms due
to inflammation and/or joint damage.
Treatment and Management-Systemic
• The treatment approach varies depending on
whether the symptoms arise from inflammation
or joint damage making the differentiation vital.
• There is no curative treatment for RA
– treatment is to minimize inflammation
– minimize damage and
– maximize patient functioning.
• Pharmaceutical agents inhibit inflammatory
responses
– have traditionally been used in a stepwise approach
from weakest to strongest.
Treatment and Management-Systemic
• Current Tx regimens utilize a step-down approach
with initiation of one or more DMARD’s at time of
diagnosis.
• RA most destructive early in disease
• “Easier” and more effective if Tx initiated early.
• DMARD-disease modifying antirheumatic drug
– these drugs not only reduce inflammation but also
change the immune response in a long-term and more
dramatically than NSAID’s
– give chance of permanent remission
Case
• 48 yr old white female presents with acute loss of
vision in her right eye and decreased vision in her
left
– She was scheduled 2 weeks previously for an eye exam on a
referral from her PCP but had fallen and was unable to make that
appointment
– She reports that her vision in her right eye seems to be getting
worse over the past several weeks.
– Was diagnosed with diabetes 1.5 years ago
• BS control has been erratic with range between between 6.713.3 (120-240)
• Last A1C: 9.1
Blood Sugar
• Hypoglycemia is typically defined as plasma
glucose 3.9 mmol/L (70 mg/dL) or less
– patients typically become symptomatic of
hypoglycemia at 2.8 mmol/L (50 mg/dL) or less
Entrance Skills/Health Assessment
VA: OD: finger count
OS: 6/12 (20/40)
CVF: OD: unable to assess
OS: temporal hemianopsia
Pupils: sluggish reactivity with a 2+
RAPD OD
SLE: corneal arcus noted, no other
significant findings
IOP: 16, 16 mmHG OD, OS
DFE: see photos
Note: not patient photos
http://content.lib.utah.edu/cdm4/item_
viewer.php?CISOROOT=/EHSLWFH&CISOPTR=159
Physical Presentation
• Upon entering the room I noted that her right hand
was twitching
– I asked her how long that had been going on and
she said about 2-3 weeks
– I asked her if she experienced headaches, to which
she said she had bad headaches that even woke her
up at night
Referral
• Contacted her PCP who reported that she had
examined the patient 3 weeks prior and had not
noted any of these findings
• Referred the patient for an immediate MRI
– wasn’t able to be scheduled until the next day
Imaging/Surgery Referral
• MRI revealed large mass in
her brain
– Patient was diagnosed with
a Craniopharyngioma
– She was referred for
immediate surgery
– Neurosurgeon reported that
she removed a tangerine
sized Craniopharyngioma
– was the largest tumor she
has ever removed
Note: not patient MRI
http://neurosurgery.ucla.edu/images/P
ituitary%20Program/Craniopharyngio
ma/Cranio_Sag_Preop_fullylabeled.jp
g
Craniopharyngioma
• Presenting signs and symptoms of increased
intracranial pressure (80%)
– Headache
– Vomiting
– Papilledema
– Loss of vision and visual field (60%)
– Diabetes (15%)
– Mental deterioration or personality change (26%)
Craniopharyngioma
• Treatment:
– Therapy is often unsatisfactory
– Total resection often results in major functional
deficits
– Partial resection followed by conventional
radiation therapy as a more conservative
approach has been recommended
Diabetes Lab Testing
• Comprehensive medical panel will include:
– Serum glucose
– Electrolytes
– Liver enzymes
– Kidney function:
• BUN and creatinine
– Elevated in renal failure
• Glomelular filtration rate
– Reduced in chronic kidney disease/renal failure
Blood Sugar
• Throughout a 24 hour period blood sugar typically maintained
between 3.9-7.8 mmol/L (70-140 mg/dL)
• [A1c (%) x 1.59] – 2.59 = average Blood Glucose (in mmol/L)
Recommendations for Management
Kidney function
• Urinalysis can be used in conjunction with blood testing to
help confirm systemic etiology of conditions
– Urine Glucose
• Any glucose in the urine is abnormal
– Urine Protein
• Proteinuria is an important indicator of renal disease
– Urine Ketones
• Ketones are byproducts of body fat metabolism formed
in the liver
• Ketonuria occurs in patients with diabetes
Kidney Function Tests:
Serum Creatinine:
- waste product that comes from the normal wear and tear
on muscles of the body.
– Kidney impairment results in rise of creatinine level in the
blood
BUN (blood urea nitrogen):
- If kidneys cannot filter wastes out of the blood due to
disease or damage, then the level of urea in the blood will
rise
Kidney function
• Kidney function is important to assess prior to
MRIs with contrast
– Gadolinium-containing contrast agents may increase
the risk of a rare, but serious, disease called
nephrogenic systemic fibrosis in people with severe
kidney failure.
– Nephrogenic systemic fibrosis triggers thickening of
the skin, organs and other tissues.
– There's no effective treatment for this serious,
debilitating disease.
Liver Tests
• Liver tests (LTs) are blood tests used to
reflect the presence of damage or
inflammation.
• alanine aminotransferase (ALT) and
aspartate aminotransferase (AST) are
the most commonly used tests
• These enzymes normally found in the
blood when liver cells are injured.
Liver Tests
• The ALT is felt to be a more specific
indicator of liver inflammation as AST
is also found in other organs such as
the heart and skeletal muscle.
• In acute injury to the liver, as in viral
hepatitis, the level of the ALT and AST
may be used as a general measure of
the degree of liver inflammation or
damage.
Liver Tests
• Bilirubin is the main bile pigment in humans
which, when elevated causes the yellow
discoloration of the skin called jaundice.
– the bilirubin may be elevated in many forms of
liver or biliary disease, it is relatively non-specific
• Allbumin is a major protein which is formed by
the liver.
– chronic liver disease causes a decrease in the
amount of albumin produced
Blood Chemistry: Lipid Profiles
Consists of:
– Serum lipids,
– Cholesterol,
• High density lipoproteins (HDL) – “good” cholesterol
• Low density lipoproteins (LDL) – “bad” cholesterol
• Very-low density lipoproteins (VLDL) – dangerous
cholesterol
– triglycerides
Current Recommended Lipid Levels
Case
• 30 BF presents with eye pain in both
eyes for the past several days
– Severe pain (8/10)
– Never had eye exam before
• PMHx:
– Has chronic bronchitis
– Rash on legs
– Has recently lost weight and has a fever
– Taking aspirin for pain
Ocular Health Assessment
VA: 6/9 (20/30) OD, OS
PERRL
FTFC
EOM”s: FROM with eye pain in all
quadrants
• SLE:
– 3+ injection,
– 3+ cells and trace flare,
– deposits on endo (see photo)
• IOP: 18, 18 mmHg
• DFE:
– see attached fundus image and
fluorescein angiography.
•
•
•
•
Sarcoid Diagnosis
Lab Test
Findings
CBC with differential
Anemia/thrombocytopenia/leukopenia
Serum calcium/24 hour calcium
Hypercalcemia
Liver/Kidney function tests
AST/ALT/BUN/Creatinine elevated in
hepatic disease
ACE (angiotensin converting enzyme)
Elevated in 60% of patients
Pulmonary x-rays
Hilar adenopathy
Blood Chemistry
• Angiotensin-Converting Enzyme (ACE)
– Found mainly in lung and liver
– Serum elevations are found in patients with
sarcoidosis, and significant levels are achieved in
pulmonary sarcoid
– Cirrhosis of the liver may produce elevated ACE
levels
– Active tuberculosis infection of the lung does NOT
produce elevated ACE levels
Diagnosis: Radiographic
• Radiographic involvement is
seen in almost 90% of patients.
• Chest radiography is used in
staging the disease:
– Stage I disease shows bilateral
hilar lymphadenopathy (BHL).
– Stage II disease shows BHL
plus pulmonary infiltrates.
– Stage III disease shows
pulmonary infiltrates without
BHL
– Stage IV disease shows
pulmonary fibrosis.
Diagnosis: Radiographic
• CT and MRI scans
may be useful in
finding granulomas
in other organ
systems
• Gallium scangallium 67 has been
found to accumulate
in active sarcoidal
tissue
Gallium Scan:
Lacrimal/parotid gland,
Hilar glands
Stages of Syphilis
Syphilis Diagnosis
• Typical diagnosis is with blood tests using
nontreponemal and/or treponemal tests.
– Nontreponemal test are used initially and
include:
• venereal disease research laboratory (VDRL)
• rapid plasma reagin (RPR)
• chemiluminescent microparticle immunoassay
(CMIA)***
*** primary screening test for patients suspected of being
exposed to syphilis
Syphilis Diagnosis
• False positives can occur with some viral infections
such as (varicella and measles), as well as with
lymphoma, tuberculosis, malaria, endocarditis,
connective tissue disease, pregnancy
– confirmation is required with a treponemal test such
as:
• treponemal pallidum particle agglutination (TPPA)
or
• fluorescent treponemal antibody absorption test
(FTA-Abs)
• The FTA-ABS test checks for antibodies to the bacteria
that cause syphilis and can be used to detect syphilis
except during the first 3 to 4 weeks after exposure to
syphilis bacteria..
Tuberculosis
• Difficult to culture the slow-growing organism in the
laboratory (it may take 4 to 12 weeks for blood or sputum
culture).
• A complete medical evaluation for TB must include:
– a medical history,
– a physical examination,
– a chest X-ray,
– microbiological smears,
– and cultures.
• It may also include a tuberculin skin test, a serological test.
– The interpretation of the tuberculin skin test depends
upon the person's risk factors for infection and
progression to TB disease, such as exposure to other
cases of TB or immunosuppression
Tuberculosis
• Currently, latent infection is diagnosed in a
non-immunized person by a tuberculin skin
test, which yields a delayed hypersensitivity
type response to an extract made from M.
tuberculosis.
• Those immunized for TB or with past-cleared
infection will respond with delayed
hypersensitivity parallel to those currently in
a state of infection, so the test must be used
with caution, particularly with regard to
persons from countries where TB
immunization is common
Tuberculosis
• The newer interferon release assays (IGRAs)
overcome many of these problems.
– IGRAs are in vitro blood tests that are more
specific than the skin test.
– IGRAs detect the release of interferon gamma
in response to mycobacterial proteins
– These are not affected by immunization or
environmental mycobacteria, so generate fewer
false positive results.
Erythrocyte Sedimentation Rate
This measures the height of RBC’s settling out of
plasma per hour
ESR
Males: Age/2
Good sensitivity but poor
specificity. Takes time for
the levels to become
detectable
Females: (Age + 10)/2
High: Indicative of giant cell
arteritis but normal levels
do not exclude GCA as a
diagnosis
Giant Cell Arteritis
• vessels most often involved are the
arteries over the temples,
– GCA = "temporal arteritis.”
• symptoms, such as fatigue, loss of
appetite, weight loss or a flu-like
feeling
– pain in the jaw with chewing (jaw
claudication).
– Sometimes the only sign of GCA is
unexplained fever.
– Less common symptoms include pains in
the face, tongue or throat.
Giant Cell Arteritis
• GCA is a clinical diagnosis!
• If patient meets criteria of
clinical symptoms then
treatment will be started
regardless of whether lab test
or biopsy are positive
• Treatment should be started
before lab results are back.
Hemogram
• C-Reactive Protein
– Normal = no CRP
– Abnormal serum glycoprotein produced by liver during acute
inflammation
– Disappears rapidly once inflammation subsides
– 4 hour fast from food/fluids
– Alternative to ESR
– More informative
• ESR high in most elderly
• Elevated in conditions such as: temporal arteritis, preseptal
cellulitis, endophthalmitis, HLA-B27 related iritis conditions.
Superior Limbic Keratoconjunctivitis
(SLK)
• inflammation of the superior bulbar
conjunctiva with predominant
involvement of the superior limbus
• adjacent epithelial keratitis and a
papillary hypertrophy of the upper
tarsal conjunctiva.
• association between thyroid
abnormalities and SLK
Superior Limbic Keratoconjunctivitis
(SLK)
• mimicking disorder has been encountered in
soft contact lens (SCL) wearers, typically with
exposure to thimerosal-preserved solutions
• middle-aged people and women are
predominantly affected
• Much higher prevalence in Graves patients
than normal population
Thyroid Gland
• T4 is the major hormone produced but has
low activity in stimulating metabolism
– T4 has a longer half-life, much higher levels of T4
than T3 are in the circulation
– T4 considered a prohormone and is metabolized
primarily in liver (87% of T3 in circulation is
formed from T4)
• T3 is 3-4 times metabolically more active than
T4
Testing recommendations?
Patients with no symptoms of thyroid disease and no
obvious risk factors have a low likelihood of thyroid
disease.
In most situations, TSH is the more sensitive indicator of
thyroid status. If further thyroid function tests are
indicated they can be subsequently added by the
laboratory, or the GP usually without the need to retest
the patient.
Thyroid Testing Algorithm
Key points about Grave’s disease:
 Most common cause of eyelid retraction
 Most common cause of bilateral or unilateral proptosis.
 More common in women
 Associated with hyperthyroidism in 90% of patients; 6% are
euthyroid
 Smoking is associated with increased risk and severity of
ophthalmopathy.
 The course of ophthalmopathy does not necessarily parallel the
activity of the thyroid gland or the treatment of thyroid
abnormalities.
Grave’s disease/Thyroid
Ophthalmopathy
Clinical signs
• Eyelid retraction- most common sign
• Lid lag
• Proptosis
• Restrictive extraocular myopathy
• Optic neuropathy
Other clinical features:
• Most frequent ocular symptom is pain or
discomfort (30%)- often the result of dry
eyes
• Diplopia- 17%
• Lacrimation/photophobia- 15-20%
• Blurring of vision- 7.5%
CBC with Differential
• Red blood cell count (RBC). RBC count is simply the
number of erythrocytes (in millions) per cubic
millimeter (mm3) or micro-liter (µL). It does not give
the detailed information necessary to determine how
well RBCs are functioning.
• Hemoglobin (Hb). This represents the amount of
oxygen-carrying protein (hemoglobin) in a sample and
reflects the number of RBCs present.
• Hematocrit. Provides a value related to the percentage
of total blood volume that is comprised of red blood
cells. It is closely related to hemoglobin levels.
CBC with Differential
• Red blood cell indices. Helpful in classifying anemias, these
indices provide information such as RBC size, weight and
hemoglobin concentration.
• White blood cell count (WBC) and differential. A WBC count
reflects the number of WBCs per µL. The differential provides
detailed information about the types of WBCs present, along
with percentages. This information is useful in the differential
diagnosis of certain disease states.
• Platelet count. This represents the number of platelets per µL
and is useful in the diagnosis and management of blood clotting
disorders and other diseases.
Why Order a CBC Diff
• helpful for patients with persistent infections,
recurrent inflammation, or in those who
exhibit signs of anemia or leukemia
• part of a battery of tests performed prior to
surgery
• monitor patients for negative side effects
associated with certain medications
– E.g. acetazolamide (Diamox)
Why Order a CBC Diff
• cases of recurrent or bilateral uveitis, may be
useful in identifying a possible non-specific
systemic etiology
– an elevated WBC count (leukocytosis) may be
present with underlying bacterial infections
– elevated lymphocyte count (lymphocytosis) may
be present with viral infections
– Parasitic causes of uveitis may reveal elevated
eosinophils (eosinophilia)
Why Order a CBC Diff
• presence of cotton-wool spots and/or retinal
hemorrhages of unknown etiology in a patient
without a documented history of diabetes
mellitus or hypertension should prompt eye
care providers to order a CBC to rule out
anemia
• CBC could detect polycythemia (elevated RBC
count), which is present in serious diseases
such as leukemia
Blood Components
• Blood volume averages approximately 5 L in
adults
– This consists of a suspension of the formed
elements (red blood cells, white cells and
platelets) in plasma
– Plasma comprises ~55% of the total blood volume
(about 3 Liters)
Blood
• Centrifuged (spun) to separate
• Clinically important hematocrit
– % of blood volume consisting of erythrocytes (red
blood cells)
– Male average 47; female average 42
• Plasma at top: water with many ions, molecules,
and 3 types of important proteins:
– Albumin
– Globulins
– Fibrinogen
73
Blood Components
• Erythrocytes (Red Blood Cells)
– Multiple functions; most importantly – O2 delivery
• O2 is bound by haemoglobin within the cell
– Accounts for 97% of the normal O2 carrying capacity
• Normal haemoglobin values are in the range of:
– Men = 14 – 16 g/dL
– Women = 12 – 14 g/dL
• Low haemoglobin concentration = anemia
Blood Components
• Erythrocytes (Red Blood Cells)
– Red blood cell production (erythropoiesis) occurs in
the bone marrow
• The kidney controls RBC production via a hormone called
erythropoitin
– The amount released depends on the O2 delivery to the renal
cells
» Note it is O2 delivery, not haemoglobin concentration
– Aging erytrhrocytes are destroyed, often in the
spleen, after an average life span of 120 days
Blood Components
• Erythrocytes (Red Blood Cells)
– RBC production and haemoglobin syntheses
require adequate supply of vitamins B12 and folic
acid, as well as the mineral iron.
• Deficiencies in these may cause anemia
Blood Components
• Erythrocytes (Red Blood Cells)
– Erythrocyte sedimentation rate (ESR)
• In an undisturbed vertical column of anticoagulated blood,
erythrocytes slowly settle out, leaving plasma above
• The normal values lie in the range of 5 – 10 mm/hr
• This rate of sedimentation increases in certain diseases
• High ESR values are often associate with an increase in
immunoglobulins
__RBC
Leukocytes
neutrophil
eosinophil
basophil
small lymphocyte
AKA WBCs: white
blood cells
Are complete cells
Function outside the
blood
Note the size difference
compared to erythrocytes
monocyte
78
Blood Components
• Leucocytes (White Blood Cells)
– WBC’s are vitally important for:
• Disposal of damaged and aging tissue
• Immune responses which protect us from infections
and cancer cell proliferation
Hemogram
• Eight components of the Hemogram (Complete
Blood Count):
–
–
–
–
–
–
–
–
Hematocrit
Hemoglobin (Hb)
Mean Corpuscular Volume (MCV)
Mean Corpuscular Hemoglobin (MCH)
Platelet Count
Mean Platelet Volume
Red Blood Cell Count (RBC)
White Blood Cell Count
Hematocrit
• Hematocrit is a measure of the percentage
of the total blood volume that is made up
by the red blood cells
• The hematocrit can be determined directly
by centrifugation (“spun hematocrit”)
– The height of the red blood cell column is
measured and compared to the column of the
whole blood
Hematocrit (HCT)
HCT
Males: 40-54%
Low: anemia
Females: 34-51%
High: fluid loss due to
diarrhea, dehydration or
burns
Hemoglobin (Hgb)
Hb
Males: 140 – 174 g/L
Low: anemia
Females: 123 – 157 g/L
High polycythemia, living at
higher altitudes, smokers
Mean Corpuscular Volume
• The MCV is a measure of the average
volume, or size, of an RBC
• It is determined by the distribution of the
red blood cell histogram
– The mean of the red blood cell distribution
histogram is the MCV
Use of MCV Result
• The MCV is important in classifying
anemias
– Normal MCV = normocytic anemia
– Decreased MCV = microcytic anemia
– Increased MCV = macrocytic anemia
Mean Corpuscular Volume
MCV
Normal: 80 – 100 fL
Low: iron deficiency
anemia, thalassemia
High living at higher
altitudes, vitamin B12 or
folate deficiency, recent
blood loss
Platelet Count
Necessary for clotting and repairing damaged blood vessels
PLT
Normal: 130 – 400 x 109 / L
Low: autoimmune
disease, blood loss,
anticoagulant medications,
High: smokers, chronic
bleeding and leukemia
Hemogram
• Red Blood Cell Count (RBC) 2,3,4
– Female = 4.0 – 5.2 x 1012 / L
– Male = 4.4 – 5.7 x 1012 / L
– Tells the clinician the number of erythrocytes
– Below normal = anemia
– Above normal = polycythemia
– Abnormal RBC can lead to cotton-wool spots, hemes, Roth
Spots, mid-peripheral or peripheral retinal hemes
Hemogram
• White Blood Cell Count (WBC) 2,3,4
– Normal = 4 – 10 x 109 / L
–
–
–
–
–
–
–
With differential :
Segmented neutrophils = 2 – 7 x 109 / L
Band neutrophils = <0.7 x 109 / L
Basophils = <0.10 x 109 / L
Eosinophils = <0.45 x 109 / L
Lymphocytes = 1.5 – 3.4 x 109 / L
Monocytes = 0.14 – 0.86 x 109 / L