Patient History & Laboratory Values

Patient Assessment Overview

Patient assessment is the systematic review of the patient's history and data before and during care. For this lesson we cover:

• Patient History
• Chart Review
• Laboratory Results

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Patient History

Patient history consists of four components:

1. Background Information
2. Past Medical History
3. Family Medical History
4. Occupational / Environmental History

Background Information

• Explains who the patient is and what type of disease they're likely to develop
• Gives information of previous illnesses and care
• Includes factors that may affect care (e.g., cultural, religious)
• Provides screening information

Past Medical History

May include:

• Illnesses since birth
• Surgeries / Hospitalizations
• Allergies
• Medications
• Drug and smoking history — age started? type? how much? if quit, how long ago?

Family Medical History

Purpose: learn the health status of blood relatives. Record of disease with hereditary links (example: cystic fibrosis).

Includes: parents, siblings, grandparents, uncles, and aunts.

Looking for possible hereditary-linked pulmonary and cardiovascular diseases such as:

• Asthma
• Lung cancer
• Cystic fibrosis
• Emphysema
• Neuromuscular disorders
• Sleep disturbances

Occupational / Environmental History

• Gathers information of possible work- or geography-related exposures
• Exposure to asbestos, coal, dusts, fumes, or gases
• Family members can also be exposed — ask if family members worked in areas with increased risk of exposure

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Chart Review

Review of the patient's notes:

• Admission Note
• Progress Notes
• Physician Orders
• Clinical Notes
• DNR / DNI / CMO

Admission Note

Written by the admitting physician with important facts pertaining to the reason the patient has been admitted to the hospital. Provides the patient's baseline status.

Progress Note

Daily annotations by the attending physician or nurse. Details patient's progress to treatment goal(s).

Physician Orders

Techniques and treatments a physician believes are needed to provide the best care for the patient.

Clinical Note

The assessment performed by the physician's team.

DNR / DNI / CMO

• Verify order in the patient chart
• Ensure patient wristband is in place
• Discuss with care team

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Laboratory Values

Four main categories:

1. Complete Blood Count (CBC)
2. Basic Metabolic Panel (BMP)
3. Microbiology Tests
4. Coagulation Tests

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Complete Blood Count (CBC)

Overall quantity assessment of:

• White Blood Cells (WBC)
• Hemoglobin (Hgb)
• Hematocrit (Hct)
• Red Blood Cells (RBC)
• Platelets

White Blood Cells (WBC)

Primary role: fighting infections.

Normal range: 4,000 – 11,000

WBC Types

WBC Abnormalities

• Leukocytosis — increased WBC. Sign of inflammatory response, most commonly significant infection. When > 16,000, indication for antibiotics.
• Leukopenia — decreased WBC. Immunosuppressed, increased risk of infection.

Red Blood Cells (RBC)

Supplies oxygen to the tissues.

Normal range: 4 – 6 million/mm³

• Anemia — decreased RBC. Occurs with blood loss (hemorrhage) or inadequate production. Reduces oxygen-carrying capability → more likely to experience tissue hypoxia.
• Polycythemia — increased RBC. Body responds to low tissue oxygen by releasing erythropoietin (EPO), which stimulates bone marrow to produce more RBCs. Increases blood viscosity. Seen in chronic tissue hypoxemia (COPD) and people living at high altitudes.

Hemoglobin (Hgb)

Carries oxygen — 1.34 mL O₂ per gram of Hgb.

Hematocrit (Hct)

The portion of whole blood that is RBCs. Reflects hydration status.

Platelets

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Basic Metabolic Panel (BMP)

• Most-ordered lab — standard to assess overall health
• Tests important electrolytes, fasting glucose, and two renal function tests (BUN & creatinine)

Sodium (Na⁺)

Normal: 135 – 145 mmol/L — primary extracellular cation. Crucial for fluid balance and nerve impulse conduction.

• Hypernatremia (↑ Na⁺) — body loses large amount of water compared to sodium lost. Caused by profuse sweating, diarrhea, and renal disease.
• Hyponatremia (↓ Na⁺) — excess water intake or fluid retention. Caused by drinking too much water, excessive ADH secretion, severe vomiting/diarrhea, CHF, and renal failure.

Potassium (K⁺)

Normal: 3.5 – 5.0 mmol/L — primary intracellular cation. Crucial for normal heart and kidney function and acid-base balance.

• Hyperkalemia (↑ K⁺) — caused by metabolic acidosis, kidney failure.
• Hypokalemia (↓ K⁺) — caused by metabolic alkalosis, excessive excretion.

Chloride (Cl⁻)

Normal: 98 – 106 mEq/L — primary extracellular anion. Crucial for acid-base balance.

• Hyperchloremia — excessive chloride administration, metabolic acidosis, diabetes insipidus.
• Hypochloremia — prolonged severe vomiting, metabolic alkalosis, severe burns.

Total CO₂ (TCO₂)

Normal: 22 – 29 mEq/L

• Decreased TCO₂ — metabolic acidosis, hyperventilation, severe diarrhea
• Increased TCO₂ — ventilatory failure

Glucose

Normal: 70 – 105 mg/dL — primary energy source for body tissues and blood cells.

• Hyperglycemia — mostly caused by type I or II diabetes; also medications, acute stress, pancreatic dysfunction.
• Hypoglycemia — relatively uncommon; caused by excessive insulin administration or dietary intake.

Blood Urea Nitrogen (BUN)

Normal: 7 – 20 mg/dL

• Increased — acute kidney disease, chronic renal failure
• Decreased — liver disease, malnutrition

Creatinine

Normal: 0.7 – 1.3 mg/dL

Both BUN and creatinine are used to assess renal function:

• Elevation = kidney disease
• Decreased = liver disease

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Microbiology Tests

Three tests:

• Sputum Gram Stain
• Sputum Culture
• Acid Fast

Sputum Gram Stain

Indicated for patients suspected to have an infection in the lungs or airway.

Purpose: determine the specific microorganism causing the infection in order to choose the best antibiotic.

Procedure: performed in a laboratory — apply a staining solution, analyze under a microscope to verify sample quality, then introduce the gram stain reaction.

Sputum Culture

• Done after sputum sample is found to be adequate
• Once the organism matures, it's examined microscopically to determine exact sensitivity and proper antibiotic therapy
• Results: 24 – 48 hours

Acid Fast

Rapid and effective method for determining tuberculosis. Perform a gram stain followed by an acid wash. If the acid wash does not weaken the cell wall enough to remove the color dye, the organism is considered an acid-fast bacterium.

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Coagulation Testing

• Helps diagnose the cause of unexplained bleeding or inappropriate blood clots
• Monitors patients on blood thinners
• Measured by puncturing the skin and timing how long bleeding takes to stop

Prothrombin Time (PT)

• Measures how much time it takes for blood plasma to clot
• Normal: 12 – 15 seconds
• Indicated for patients on Warfarin (Coumadin)

International Normalized Ratio (INR)

• Ratio of a patient's PT to the normal mean PT
• Normal: 0.8 – 1.1
• Too high — patient may be in danger of bleeding out
• Too low — patient's blood clots very fast

Activated Partial Thromboplastin Time (APTT)

• Normal: 23 – 32 seconds
• Indicated for patients on Heparin