Laboratory Review for Long Term Care

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Laboratory Review for Long Term Care
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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

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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)

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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

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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
• Cant see the branches through all the leaves!
• Dont 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

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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

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Red Blood Cells and Anemias
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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

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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

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Hgb

• Decreased anemias, cirrhosis of liver,
  leukemias, Hodgkins disease, cancer (intestine,
  rectum, liver or bone), kidney disease
• Increased Dehydration, COPD, CHF, polycythemia

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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

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Serum Iron repeated info??

• Decrease iron deficiency, inflammatory bowel
  disease, grastric surgery
• Increase Hemolytic, pernicious and folic acid
  anemias, liver damage, lead toxicity,

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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

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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

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Who is at risk for B12 depletion?

• Lack of intrinsic factor
• Autoimmune gastritis
• Gastectomy patients
• No animal protein
• Liver failure
• Malabsorption Crohns disease, celiac disease,
  gastric by-pass surgery

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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

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Folic Acidaka 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

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Drugs that can block folic acid synthesis

• TMP/SFX (Bactrim, Septra)
• Reheumatrex (Methotrexate)
• Phenytoin (Dilantin)

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White Blood CellsWBCA component of a complete
Blood Count
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White Blood CellsWBC

• 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.

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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

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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

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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

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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)

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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

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Coagulation
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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?

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Aging and Clotting

• Amount of fibrinogen increases by 1 per year
  after age 30

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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

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Platelets

• Decrease anemia, liver disease, kidney disease,
  idiopathic thrombocytopenia purpura (ITP),
  cancer, leukemia
• Increase pulmonary embolism, tuberculosis,
  polycthemia, trauma, post-splenectomy, metastatic
  carcinoma

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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

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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

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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

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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

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Kidney Function
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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

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Albumin

• Decreased malnutrition, liver failure, renal
  disorders, prolong immobilization
• Increased dehydration, severe vomiting, diarrhea

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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

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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

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• Increase renal failure, shock, acute MI, CHF,
  diabetic neuropathy
• We have a serum creatinine, so why calculate a
  creatinine clearance?

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• 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
  productionin 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

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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

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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

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Thyroid
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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?

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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

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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
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TSH

• Decrease excessive thyroid hormone replacement,
  Graves disease, primary hyperthyroidism
• Increase primary hypothyroidism, thyroid hormone
  resistance

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Clues about Dehydration
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• 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

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2 kinds of total body water fluid loss

• Dehydration loss of body water mainly from
  intracellular compartments
• Volume depletion loss of extracellular fluid

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• 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

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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 bodys
  cells, maintain a healthy water balance and
  stabilize the bodys pH level

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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

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PotassiumK

• 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)

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K

• Decrease vomiting, diarrhea, dehydration,
  malnutrition, stress, diabetic acidosis
• Increase acute renal failure, acidosis, crushing
  injury, Addisons disease

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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,
  Hodgkins disease, multiple myeloma
• Decrease dehydration, sever diarrhea, diabetic
  acidosis, emphysema, transient cerebral ischemia
  may indicate fluid overload, dietary deficiencies

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Albumin

• Remember albumin helps keep water inside blood
  vessels
• High albumin almost always synomonous with
  dehydration

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Urinalysis
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Urinalysis
Appearance Colour Odor pH Protein Specific Gravity Leukocyte esterase, Nitrates, Ketones, Glucose Crystals WBC WBC casts RBC RBC casts Clear Light straw to dark amber No odor/aromatic 4.5-8 2-8 mg/dl 1.005-1.030 Negative 0 3-4 Occasional hyaline Less than 2 0
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Interpretation of abnormal Urinalysis

• Urine pH a. Elevated alkalemia, UTI,
  vomiting,diet high in fruits vegetablesb.
  Decreased acidemia, DM, starvation, COPD, diet
  high in protein
• Specific Gravity
• a. Elevated dehydration, decreased renal blood
  flow, glycosuria, proteinuria, vomiting,
  diarrheab. 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

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Urinalysis for Kidney Disease

• Nephritis 1-2 protein
• Nephrosis 3-4 protein

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You have the lab results now what?

• Timeliness depends on results and clinical
  situation
• Report other key clinical data with results
• Documentation of communication

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The End
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Bones and Red Cell Production

• Nutritional Status greatly affects the bodys
  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.

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Erythrocyte Sedimentation RateESR

• 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)

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ESR

• Decreased CHF, degenerative arthritis, angina
• Increased hepatitis, cirrhosis of liver,
  rheumatoid arthrtis, rheumatic fever, acute MI,
  cancer (stomach, colon, breast, liver, kidney),
  Hodgkins disease, multiple myeloma, bacterial
  endocareditis, gout