Laboratory Review for Long
Term Care
Why is lab interpretation so difficult
in the elderly?
• physiologic changes associated with aging can
alter ‘normal values’
• high prevalence of chronic conditions
• changes in nutrition and fluid consumption
• lifestyle changes
• pharmacologic regimes
• gender, body mass, diet, stress
• collection site, collection time, tourniquet
application, specimen transportation
Frame of Reference
• Frame of Reference ranges are obtained
by determining the mean of a random
sample of HEALTHY individuals (usually
between the ages of 25 and 40)
Changes in lab values can be
classified into 3 groups:
• those that change with aging
• those that do not change with aging
• those for which it is unclear whether aging,
disease, or both influence the
Too many numbers to know!?
A wise wound care nurse once said:
“Look at the WHOLE patient and not just the HOLE”
This applies to laboratory interpretation as well
Must consider a total assessment rather than simply relying
on laboratory diagnostic testing
“Can’t see the branches through all the leaves!”
Don’t get too focused on the actual laboratory values – you
do need to be aware of normals, but think about the
processes that are responsible for the values
Today we will attempt to…
• Review basic laboratory values and how
they relate to common geriatric health
concerns
• Remember – with each lab value, there is
a pathophyisology text book written on the
associated topics. Use this review as an
assessment for your own learning needs
Red Blood Cells and Anemias
Hemoglobin
(HGB) Part of a complete blood
count (CBC)
• Red blood cells (where Hgb is found) live for
approximately 100 days
• In a person with Sickle Cell Anemia, red cells
only live for approximately 40 days
• Changes in erythrocytes (red blood cell)
synthesis caused by changes in iron and vitamin
B12 absorption
• Impaired erythrocyte production, blood loss,
increased erythrocyte destruction or a
combination, will lower haemoglobin levels
Hgb
• Lower than normal levels may be acceptable!
Due to aging changes or illness
• Most often, anemia is associated with a chronic
condition such as renal insufficiency or gastric
bleeding
• A reduction in hemoglobin can result in
decreases O2 and lead to increased fatigue
• May present with SOB, fatigue, parethesia –
often vague symptoms attributed to old age
Hgb
Decreased: anemias, cirrhosis of liver,
leukemias, Hodgkin’s disease, cancer
(intestine, rectum, liver or bone), kidney
disease
Increased: Dehydration, COPD, CHF,
polycythemia
Anemia and the Elderly
• According to the Canadian Journal of CME, up to 44% of
the geriatric population has some form of anemia
• Decreased serum iron in many older adults, resulting in
iron deficiency anemia
• Theory: normal age related decrease in hydrochloric acid
(HCl) in the stomach affects iron absorption in
stomach….HCLI is important in facilitating iron
absorption in intestines
• Medications that decrease HCl secretion!!!
• Decrease in iron storage and iron deficiency anemia,
commonly caused by inadequate dietary intake of iron or
loss of iron through chronic or acute blood loss
Serum Iron – repeated info??
Decrease: iron deficiency, inflammatory
bowel disease, grastric surgery
Increase: Hemolytic, pernicious and folic
acid anemias, liver damage, lead toxicity,
Interpreting Anemia with
MCV(Mean Corpuscular Volume)
MCV:
Microcytic (MCV low)
• Iron deficiency anemia
• Anemia of chronic disease
Macrocytic (MCV high)
- Deficiency of vitamin B12, folic acid
- Pernicious anemia – lack of ability to absorb vitamin B12 from food
- Hypothyroidism
- Alcoholism
Normocytic (MCV normal)
- Acute blood loss
- Anemia of chronic disease
- Aplastic anemia
- Hemolytic anemia
B12
• B12 stored in the liver for 5-7 years – 2000 to
5000 mcg
• Approx 1mcg per day is used for making RBCs
• Keeps the myelin in the CNS and PNS healthy
• Involved in making serotonin – our happy
hormone
• Takes about 5-7 years of no B12 to deplete
stores
Who is at risk for B12 depletion?
•
•
•
•
•
•
Lack of intrinsic factor
Autoimmune gastritis
Gastectomy patients
No animal protein
Liver failure
Malabsorption – Crohn’s disease, celiac
disease, gastric by-pass surgery
B12 Deficiency
• A leading cause of nutritional dementia
• One of the top causes of peripheral
neuropathy
• Contributes to depression
• Commonly seen in liver disease,
hypothyroidism
Folic Acid
aka Vitamin B9
• Used for synthesizing DNA, repairing DNA
• Aiding in rapid cell division and growth
• Many folic acid fortified foods, therefore, difficult
in north America to be deficient – but you have
to eat it!!
• Folate deficiency symptoms include:
• Diarrhea, SOB, peripheral neuropathy, mental
confusion, cognitive decline, depression, sore or
swollen tongue, peptic or mouth ulcers,
headaches, cardiac palpitations, irritability,
behavioural disorders
Drugs that can block folic acid
synthesis…
• TMP/SFX (Bactrim, Septra)
• Reheumatrex (Methotrexate)
• Phenytoin (Dilantin)
White Blood Cells
WBC
A component of a complete Blood
Count
White Blood Cells
WBC
• Immunity gradually declines after age 30-40; may also
result from disease, infection or sepsis, or medications,
analgesics, steroids
older persons with infection or sepsis do not always mount
the same WBC response (i.e. no fever).
If someone is older and confused, but has a WBC is still in
the “normal range,” look closely at the absolute
neutrophil levels;
if you see a rise in this, they may have an occult infection
despite having a “normal” WBC.
White Blood Cells (WBC)
Increased: acute infections, tissue necrosis,
alcoholism, lupus, rheumatoid arthritis,
hemolytic anemia, parasitic diseases,
stress
Decreased: specific disease (myeloma,
collagen disorders), infection or sepsis
(pneumonia, UTI), medication (analgesic,
phenothiazides, steroids), stress,
alcoholism, rheumatoid arthrtis
Breaking down the WBC
• Neutrophils – acute inflammation, bacteria,
acute necrosis
• Lymphocytes – first responder to viruses, cells of
the immune system (T cells, B cells)
• Monocytes – macrophages in tissues, cells of
chronic inflammation
• Eosinophils – cells that respond to parasites and
allergies
• Basophils – contains histamine
Neutrophils
• Phagocytic functions – they love to eat!
• Cell of acute inflammation
• First responder to bacterial invasion (strep,
staf, E. Coli, H. flu, menigococcus,
Pseudomaonas, C. diff)
• Loves acute necrotic tissue (gangrene, MI,
appendicitis) Remember – loves to eat!
• Fastest dividing cell in an adult
Drugs and Neutropenia
• Cimetidine (Tegament), ranitidine (Zantac)
• Carbamazepine (Tegretol); phenytoin
• Captopril (Capoten), enalipril (Vasotec),
amiodarone, quindine
• Zidovudine (Retrovir)
• Clonapine (Clozaril)
• Antibiotics including metronidozole (Flagyl),
gentamiacin, clindamycin, imipenem,
tetracylines
• Azothiaprine (Imuran)
Prednisone and Neutrophils
• Inhibits migration and degranulation –
halts the antinflammatory process
• Prednisone increases blood sugar by
stimulating glycogenolysis in liver and
hyperglycemia inhibits funciton of
neutrophils
• Fever increases migration of neutorphils
Coagulation
Coagulation
• The process by which blood forms clots
• Damage to blood vessel epithlial lining;
exposure of blood to protiens (tissue factors)
initiates changes to platelets and fibrinogen
(clotting factor)
• Platelets immediately form plug at site of injury
• Then fibrin strands (thought clotting cascade) to
strengthen platelet plug
• What conditions increase risk of clotting?
Aging and Clotting
• Amount of fibrinogen increases by 1% per
year after age 30
Platelets
• Aging usually causes decline in bone marrow
function, may contribute to lower platelet counts
and decreased platelet function
• BUT platelet adhesiveness increases with age,
with no change in numbers
• Therefore, ability to regenerate platelets may be
inadequate, leading to inadequate clotting…
• hidden blood loss? Occult blood in stools,
emesis
Platelets
• Decrease: anemia, liver disease, kidney
disease, idiopathic thrombocytopenia
purpura (ITP), cancer, leukemia
• Increase: pulmonary embolism,
tuberculosis, polycthemia, trauma, postsplenectomy, metastatic carcinoma
Coagulation Profile
• Platlet norms:
• Hemostasis: platelet count above 100 000
• 50 000 to 100 000 may show increased
bruising
• Less than 50 000 need monitoring
• Hemorrhage under 10 000
• INR protocols for residents on Coumadin
What time do most Myocardial
Infarctions happen?
• Liver produces clotting factors, cholesterol,
glucose, inflammatory mediators overnight then
disperses them to the body in the morning
• Inflammatory mediators are highest in the am –
triggers plaque rupture
• Platelets are stickiest in the early am due to
highest blood sugar
• Platelet plug forms, triggers clotting cascade
• Takes 2 hrs to form MI
• Therefore MI at 0900
• ASA inhibits platelet aggregation
What time will a Pulmonary
Embolism happen?
DVT (clot) formation from a few hrs to a few
weeks
Attached to the deep veins of the legs and
pelvis
Breaks off in the early am and travels to
lungs
PE at 0730
Medications and Platelets
• Gingko – increases blood flow to lower
limbs
• Glucosamine – affects blood suger
• Ginseng – NA and H2O retiner
• Grapeseed extract –
• Garlic –
• Heparin/Plavix – decreases platelet counts
Kidney Function
Albumin
• Produced in the liver
• Helps keep water inside the blood vessels
to prevent dehydration
• Albumin levels decrease each decade
over age of 60 with marked decrease over
90yr
Albumin
• Decreased: malnutrition, liver failure, renal
disorders, prolong immobilization
• Increased: dehydration, severe vomiting,
diarrhea
Total Protein
• Changes in protein may reflect decreased
liver functioning, or inadequate nutritional
intake
• High: dehydration, vomiting
• Low: decreased intake/absorption, edema,
malnutrition, low protein diet, severe liver
disease, chronic renal failure
Creatinine
• What is creatinine? A break-down product
of creatine phosphate in muscle and is
filtered out of the body by the kidneys
• Age related decrease in functioning renal
tissue is 30-45%
• Which leads to a decrease in the
glomerular filtration rate (GFR)
• Which leads to a decline in creatinine
clearance
• Increase: renal failure, shock, acute MI,
CHF, diabetic neuropathy
We have a serum creatinine, so why
calculate a creatinine clearance?
• A simple creatinine level can overestimate renal
function…
• Reduction in lean body mass, decreased dietary
protein intake and/or decreased hepatic function
may lead to a decrease in the end products of
metabolism, and hence, less creatinine
production…in a blood test, the creatinine level
may appear in ‘normal range’ due to these
above mentioned changes in the elderly body
• Therefore, serum creatinine values remain
within normal limits despite diminished renal
clearence
Creatinine clearance
• A measure of how effectively kidneys are
filtering creatinine out of body
• Decrease: renal impairment,
hyperthyroidism, thiazide use
• Increase: hypothyroidism, renal vascular
hypertension
• Formula for creatinine clearence
Changes in renal function can also
be linked to:
• Chronic urinary tract infections, benign
prostatic hypertrophy, prostatic tumors,
diabetic neuropathy
• One of the early signs of renal failure is
mild anemia
Thyroid
Thyroid Function Tests
• Hypothyroidism in 2-6% of general
population over age 70
• Free T4 levels decreases progressively
with age
• T3 typically show a 20% change during
the lifetime of an older adult
• How does the thyroid affect the older
adult?
Thyroid and geriatrics
• Thyroid regulates metabolism, promotes skeletal growth
and brain development, stimulates the heart and
regulates energy production
• Hypothyroidsm can be masked by clinical features that
share symptoms with aging including: general slowing of
mental and physical function, tendency of low body
temperatures, cold intolerance, weight gain, constipation,
hardening of the arteries, elevation of cholesterol,
elevation of blood pressure and anemia
• Hyperthyroidism associated with irregular heart rhythms,
congestive heart failure, nervousness, sweating, weight
loss, muscle weakens
TSH
T4
T3
Interpretation
High
Normal
Normal
Mild (subclinical
hypothyroidism
High
Low
Low or Normal
Hypothyrodism
Low
Normal
Normal
Mild
(subclinical)
hyperthyroidism
Low
High or Normal
High or Normal
Hyperthyroidism
Low
Low or Normal
Low or Normal
Nonthyroidal
illness; rare
pituitary
hypothyroidism
TSH
• Decrease: excessive thyroid hormone
replacement, Graves’ disease, primary
hyperthyroidism
• Increase: primary hypothyroidism, thyroid
hormone resistance
Clues about Dehydration
• Water is 55-65% of body mass
• 2/3 of water is intracellular (lean tissue)
• 1/3 extracellular – of that, 25% intravascualr (8%
total body water)
• With aging, decline in total body water, in both
extra and intracellular fluid volume
• Up to 30% more fat than lean muscle
• The decrease in total body water, alterations in
water regulation leads to increased vulnerability
• In response to heat/exercise, older adults loos
more intracellular fluid and less intersitial fluid
2 kinds of total body water fluid
loss:
• Dehydration: loss of body water mainly
from intracellular compartments
• Volume depletion: loss of extracellular fluid
• Sodium and Water depletion: diuretics,
adrenal insufficiency, renal salt wastage,
vomiting and/or diaarrhea, excessive
sweating, burns
• Water Depletion: fever, central diabetes
insipidus, nephrogenic diabetes insipidus,
essential hypernatremia, osmotic diuresis
Electrolytes
• Overall, electrolytes values remain within
standard reference values
• Electrically charged minerals found in
body tissues and blood in the form of
dissolved salts
• Help move nutrients into and wastes out of
body’s cells, maintain a healthy water
balance and stabilize the body’s pH level
Sodium
Na
Salt that enters body by food and fluids
Controlling intracellular fluid volume and water distribution
in the body
Single most abundant ion in extracellular fluid
Increase: caused by decrease in body fluid volume through
vomiting, gastric suctionoing, diarrhea, diuretics/diuresis,
burns, open wounds, diaphoresis, hyperventilation
Decrease: much more nonspecific, confusion, decreased or
changed mental status or speech patterns, postural
hypotension, dry sticky mucous membranes, thirs,
letargic, irritable, restless, muscle irritability and
spasticity, hyperrflexia, seizures, coma
Potassium
K
• Gained through dietary intake and lost by
excretion – if either is altered,
hyperkalemia or hypokalemia can rapidly
occur (a very narrow index)
• Conducts electricity in the body, crucial for
heart function, key role in skeletal and
smooth muscle contraction (which inturn
aides in normal digestive and muscular
function)
K
Decrease: vomiting, diarrhea, dehydration,
malnutrition, stress, diabetic acidosis
Increase: acute renal failure, acidosis,
crushing injury, Addison’s disease
Hematocrit (part of a CBC)
• An indicator of fluid and/or nutritional status
• Increase: cirrosis of liver, protein malnutrition,
peptic ulcer, chronic renal failure, rheumatoid
arthritis, anemia, leukemia, Hodgkin’s disease,
multiple myeloma
• Decrease: dehydration, sever diarrhea, diabetic
acidosis, emphysema, transient cerebral
ischemia may indicate fluid overload, dietary
deficiencies
Albumin
• Remember – albumin helps keep water
inside blood vessels
• High albumin almost always synomonous
with dehydration
Urinalysis
Urinalysis
Appearance
Colour
Odor
Clear
Light straw to dark amber
No odor/aromatic
pH
Protein
Specific Gravity
4.5-8
2-8 mg/dl
1.005-1.030
Leukocyte esterase, Nitrates,
Ketones, Glucose
Negative
Crystals
WBC
WBC casts
0
3-4
Occasional hyaline
RBC
RBC casts
Less than 2
0
Interpretation of abnormal
Urinalysis
Urine pH
a. Elevated – alkalemia, UTI, vomiting,
diet high in fruits & vegetables
b. Decreased – acidemia, DM, starvation, COPD, diet high in protein
Specific Gravity
a. Elevated – dehydration, decreased renal blood flow, glycosuria, proteinuria, vomiting, diarrhea
b. Decreased – overhydration, diabetes insipidus, renal failure, diuretics
Leukocyte Esterase
a. positive = UTI
Nitrates
a. positive = UTI
Ketones
a. positive = DM out of control, ETOH, fasting, starvation, high protein diet, severe stress
Casts
a. many in renal disease
WBC
a. increased = UTI
WBC Casts
a. increased = kidney infection
RBCs
a. increased = renal disease, bladder or renal tumor, trauma, anticoagulant use, menstruation
RBC Casts
a. increased = glomerulonephritis, renal infarction, lupus, vasculitis, malignant hypertension
Glucose
a. positive = Diabetes Milletus, renal disease
Protein
a. increased = Multiple Myeloma, urinary tract injury, vaginal secretions mixed in urine
Urinalysis for Kidney Disease
• Nephritis 1-2+ protein
• Nephrosis 3-4+ protein
You have the lab results – now
what?
• Timeliness depends on results and clinical
situation
• Report other key clinical data with results
• Documentation of communication
The End
Bones and Red Cell Production
Nutritional Status greatly affects the body’s ability to produce new red
cells
• Vitamin A – bone remodeling
• Vitamin B12 – combines with folic acid, iron and vitamin C to
improve production of red cells
• Vitamin C – promotes formation of collagen (structural synthesis of
bone production)
• Vitamin K – supports bone remodeling
• Vitamin E – antioxidant that preserves cellular consttuents
• Iron – essential part of blood cell production
• Magnesium – for calcium metabolism in bone
• Zinc – tissue renewal and skeletal development
• Copper – form the connective structures of bones and enhances
effectivness of vitamin D
• Hematocrit is another good indicator of nutritional status….
Erythrocyte Sedimentation Rate
ESR
• Can be ordered with a CBC
• measures rate at which red cells settle in 1
hr
• Increased rate could be presence of
inflammation (causes alteration in blood
proteins, making RBCs heavier and
causing them to settle faster)
ESR
• Decreased: CHF, degenerative arthritis,
angina
• Increased: hepatitis, cirrhosis of liver,
rheumatoid arthrtis, rheumatic fever, acute
MI, cancer (stomach, colon, breast, liver,
kidney), Hodgkin’s disease, multiple
myeloma, bacterial endocareditis, gout