1. Laboratory Values and the Older Adult
Chapter Twenty-Two
Laboratory Values and the Older Adult

2. Meaning of Laboratory Values
Many normal ranges are different for older adults.
Greater deviation from normal when under stress
Return to normal is slower.
Relationship to clinical status
Laboratory values should not be assessed in isolation
Abnormal laboratory value may indicate clinical stressor or medication side effect rather than illness.

3. Common Screening Tests
Tuberculin skin test
Borderline positive result 6–10 mm of induration
Screening method for tuberculosis
Urinalysis
Appearance: clear yellow/straw
Specific gravity: 1.005–1.035
pH: 4.5–8.0
Negative for glucose, ketones, blood, bilirubin

4. Common Screening Tests (cont’d)
Urinalysis (cont’d)
Signs and symptoms of UTI-polyuria, dysuria, frequency of urination
Types of specimens
Mid-stream clean catch
First morning or fasting
24-hour

5. Common Screening Tests (cont’d)
Stool for occult blood
Negative result: absence of test color
Test three specimens and two different sections of each stool.
Avoid red meat, vitamin C intake, iron supplements, and aspirin 2 to 3 days before testing.

6. Hematological Indicators
Complete blood count (CBC)
Values do not change with age.
Red blood cell (RBC) count
Men: 4.7–6.1 million cells per mcL
Women: 4.2–5.4 million cells per mcL
Diagnose anemia, polycythemia, other bone marrow abnormalities

7. Hematological Indicators (cont’d)
Complete blood count (cont’d)
Hemoglobin
Men: 13.8–17.2 g/dL
Women: 12.1–15.1 g/dL
Increase: polycythemia, dehydration
Decrease: anemia-the most common cause of low hemoglobin, recent hemorrhage, fluid retention, kidney disease

8. Hematological Indicators (cont’d)
Complete blood count (cont’d)
Hematocrit
Men: 47.0 ± 5.0%
Women: 42.0 ± 5.0%
Measures percentage of blood volume that packed red blood cells represent
Increased: polycythemia
Decreased: anemia, hemodilution, bone
marrow disease

9. Hematological Indicators (cont’d)
Complete blood count (cont’d)
RBC indices
MCV
Male: 78–100 fL
Female: 79–102 fL
MCH: 25–35 pg per cell
MCHC: 31%–37%
Aid in diagnosis and classification of anemias

10. Hematological Indicators (cont’d)
Complete blood count (cont’d)
White blood cell count
4,500–10,000 cells per mcL
Used to identify infectious or inflammatory processes, monitor response to chemotherapy and radiation therapy
Increased: infection, leukemia, inflammation
Decreased: bone marrow depression, viral infection

11. Hematological Indicators (cont’d)
Complete blood count (cont’d)
White blood cell differential
Neutrophils: 1.6–6.7 K/uL or 55%–70%
Eosinophils: 0–0.5 K/uL or 1%–5%
Basophils: 0–0.3 K/uL or 0%–3%
Lymphocytes: 1.2–3.4 K/uL or 16%–46%
Monocytes: K/uL or 4%–11%

12. Hematological Indicators (cont’d)
Complete blood count (cont’d)
White blood cell differential (cont’d)
Used to determine severity of infection, detect allergic reactions, identify various leukemias

13. Hematological Indicators (cont’d)
Complete blood count (cont’d)
Platelet count
130,000–400,000/mL
Required for clot formation and hemostasis
Increased: iron deficiency anemia, hemorrhage, malignancies, splenectomy
Decreased: bone marrow disease, folic acid or vitamin B12 deficiency, drug side effects

14. Hematological Indicators (cont’d)
Complete blood count (cont’d)
Prothrombin time
Normal: 11.2–13.2 seconds with an international normalized ratio (INR) of 1
Therapeutic control: 1.5–2 times normal
Determined before anticoagulation therapy and used monitored throughout anticoagulant therapy

15. Hematological Indicators (cont’d)
Complete blood count (cont’d)
Coagulation
Activated partial thromboplastin time (APTT)
Normal: 25–36 seconds
Therapeutic: 1.5–2.5 times normal control
Evaluated clotting factors of the intrinsic pathway
APTT evaluates all clotting factors by measuring the time needed to form a clot. It is more sensitive than PTT. APTT is used for monitoring anticoagulation by heparin.

16. Blood Chemistry Indicators
Blood glucose-signs and symptoms are polyuria, polyphasia; polydipsia
Fasting
Normal: 75–99 mg/dL
Older adult: increase 1–2 mg/dL per decade
Diabetes mellitus: greater than 125
Glycolated hemoglobin (HgA1C)
Normal: less than 5.7%
Prediabetes: 5.7%–6.4%
Diabetes: greater than 6.5%
Goal for diabetics: less than 7%

17. Blood Chemistry Indicators (cont’d)
Blood glucose (cont’d)
Decreased: side effects of various medications, strenuous exercise
Increased: medication side effects, recent illness or infection
Electrolytes
Sodium: 136–145 mEq/L

18. Blood Chemistry Indicators (cont’d)
Electrolytes (cont’d)
Sodium (cont’d)
Hyponatremia-low sodium level
Caused by vomiting, diarrhea, renal disorders, diuretics, congestive heart failure
Hypernatremia-high sodium level
Caused by inadequate fluid intake, diarrhea, diuretics

19. Blood Chemistry Indicators (cont’d)
Electrolytes (cont’d)
Potassium: 3.5–5.0 mEq/L-regulates cardiac conduction
Hypokalemia-low potassium level
Caused by diuretics, malnutrition, vomiting, diarrhea
Hyperkalemia-high potassium level
Caused by renal failure, injuries, acidosis,
diabetes mellitus, several medications and can be manifested by irregular heart beats

20. Blood Chemistry Indicators (cont’d)
Electrolytes (cont’d)
Calcium: 9–10.5 mg/dL
Hypocalcemia
Caused by hypoparathyroid, laxative, chemotherapy, corticosteroids
Hypercalcemia
Caused by hyperparathyroid, thiazide antidiuretics, immobilization, excessive vitamin D, calcium-containing antacids

21. Blood Chemistry Indicators (cont’d)
Electrolytes (cont’d)
Phosphate: 3–4.5 mg/dL
Chloride: 98–106 mEq/L-helps to maintain acid-base balance
End products of metabolism- along with creatinine are waste products of metabolism that are excreted by the kidneys. Increased levels of serum BUN and creatinine may indicate decreased kidney function
Blood urea nitrogen (BUN): 8–25 mg/dL-assesses renal function
Increase caused by renal disease, urinary tract obstruction, drugs

22. Blood Chemistry Indicators (cont’d)
End products of metabolism (cont’d)
Blood urea nitrogen (cont’d)
Decrease caused by severe liver failure, malnutrition, overhydration
Creatinine
Normal
Male: 0.6–1.5 mg/dL
Female: 0.6–1.1 mg/dL
Increase caused by renal disease, diabetic acidosis, starvation, diuretics
High levels indicate renal failure.

23. Blood Chemistry Indicators (cont’d)
End products of metabolism (cont’d)
Bilirubin
Total: 0.1–1.0 mg/dL
Direct: 0.0–0.4 mg/dL
Indirect: 0.1–1.0 mg/dL
Uric acid-used to help diagnose gout
Men: 3.6–8.0 mg/dL (older male: 2–8.5 mg/dL)
Women: 2.3–6.0 mg/dL (older female: 2–8 mg/dL)
Increase caused by loop diuretics, thiazides, starvation, alcohol abuse, chemotherapy

24. Blood Chemistry Indicators (cont’d)
Liver function tests
ALT: 10–56 U/L
Increase caused by liver disease, medications, cholecystitis, trauma, lead ingestion
AST or SGOT: 5–41 U/L
Increase caused by myocardial infarction, liver disease, hemolytic anemia, pulmonary emboli

25. Cardiac Indicators
Creatinine kinase (CK) or Creatine phosphokinase (CPK)
Normal
Male: 60–400 U/L
Female: 40–150 U/L
Isoenzyme values
CK-I: 0%–1%
CK-II: 3% or 0–7.5 ng/mL
CK-III: 95%–100%

26. Cardiac Indicators (cont’d)
Troponins
Troponin I: greater than 1.5 ng/mL, positive for MI
Troponin II: greater than 0.1–0.2 ng/mL, positive for MI
B-natriuretic peptide (BNP)
Normal reference is less than 100 pg/mL.
Greater than 100 pg/mL is positive for CHF.

27. Nutritional Indicators
Protein indicators
Total serum protein: 6–8 g/dL
Increase caused by dehydration, infection, diabetic acidosis, chronic alcoholism
Decrease caused by malnutrition, hepatic disease, renal disease, congestive heart failure
Albumin: 3.1–4.3 g/dL
Increase caused by multiple myeloma
Decrease caused by malnutrition, liver and renal disease, collagen diseases, rheumatoid arthritis

28. Nutritional Indicators (cont’d)
Globulins: 2.6–4.1 g/dL
Increase caused by tuberculosis, chronic syphilis, subacute bacterial endocarditis, myocardial infarction, diabetes mellitus
Iron indicators
Men: 80–180 mg/dL
Women: 30–160 mg/dL
Essential in production and function of hemoglobin

29. Nutritional Indicators (cont’d)
Iron indicators (cont.)
Ferritin: 20–400 ng/mL
Increased in hepatic disease, iron overload, leukemia, chronic renal disease
Decreased in chronic iron deficiency
Total iron-binding capacity: 250–410 mg/dL

30. Nutritional Indicators (cont’d)
Lipoproteins
Total plasma cholesterol
Desired: <200 mg/dL
Borderline: 200–239 mg/dL
High: 240 mg/dL
High-density lipoprotein (HDL)
Desired: >35

31. Nutritional Indicators (cont’d)
Lipoproteins (cont’d)
Low-density lipoprotein (LDL)
Desired: 130 mg/dL
Borderline: 130–159 mg/dL
High: 160 mg/dL
Triglycerides: 160 mg/dL

32. Nutritional Indicators (cont’d)
Lipoproteins (cont’d)
Lipid abnormalities are often familial.
Secondary causes
Diets high in saturated fat or cholesterol
Excessive alcohol intake
Estrogen supplements
Smoking
Sedentary lifestyle

33. Nutritional Indicators (cont’d)
Lipoproteins (cont’d)
Cholesterol is decreased in malnutrition, hyperthyroidism, and chronic obstructive pulmonary disease.

34. Drug Monitoring and Toxicology
Drug monitoring is important when toxic and therapeutic range is narrow.
Commonly monitored drugs
Digoxin
Therapeutic: 0.5–20 ng/mL
Toxic: 2.5 ng/mL
Signs of toxicity
Visual changes, headache, nausea and vomiting, weakness and fatigue

35. Drug Monitoring and Toxicology (cont’d)
Commonly monitored drugs (cont’d)
Theophylline
Therapeutic: 10–20 µg/mL
Toxic: 20 µg/mL
Signs of toxicity
Anorexia, abdominal discomfort, dizziness, shakiness, restlessness, palpitation, tachycardia, hypotension

36. Drug Monitoring and Toxicology (cont’d)
Commonly monitored drugs (cont’d)
Phenytoin
Therapeutic: 10–20 µg/mL
Toxic: 30 µg/mL
Signs of toxicity
Drowsiness, mental confusion, tremors, photophobia, blurred vision