Chapter 16 Interpreting Clinical and Laboratory Data. Learning Objectives. Describe what a critical value is and state its importance in clinical practice. Define the following terms related to clinical lab tests: leukocytosis, leukopenia, anemia, polycythemia, and thrombocytopenia.
Describe what a critical value is and state its importance in clinical practice.
Define the following terms related to clinical lab tests: leukocytosis, leukopenia, anemia, polycythemia, and thrombocytopenia.
Identify which electrolyte disturbances interfere with normal respiratory function.
The normal or expected boundaries for any analysis such as electrolytes, blood cells, proteins, or enzymes that would likely be encountered in healthy subjects is called a:
Common test measuring formed elements of blood
Counts & examines:
Leukocytes (white blood cells)
Erythrocytes (red blood cells)
White Blood Cell Count
WBC count above normal is called leukocytosis
Leukocytosis - common with infection, stress, & trauma.
Degree of leukocytosis depends on severity of infection
Severe infection with mild leukocytosis may represent poor prognosis
White Blood Cell Count
Below normal represents leukopenia (leukocytopenia)
Occurs with overwhelming infections & when immune system is depressed due to disease or certain cancer therapies (chemotherapy)
Diseases of bone marrow (e.g., leukemia) can cause leukopenia
White blood cells come in 5 varieties
Leukocytosis is most often due to elevation of only 1 of 5 types of white blood cells
Reduced RBC count is called anemia
Anemia is due to either blood loss or reduced RBC production by bone marrow
Anemia reduces oxygen-carrying capacity of blood
Several types of anemia exist with different causes (dietary deficiencies, chronic inflammatory disease, hereditary)
Severe anemia is treated with transfusion
Abnormal elevation of RBC count is known as polycythemia
Secondary polycythemia occurs when bone marrow is stimulated to produce more RBCs in response to chronically low blood oxygen levels
Common in people who live at an elevated altitude & in patients with chronic hypoxemic lung disease
Includes hemoglobin & hematocrit levels
Plays role of bonding with oxygen
Normal hemoglobin concentration is 12-17 g/dL
RBCs with reduced hemoglobin are smaller than normal (microcytic anemia) & lack normal color (hypochromic anemia).
An RBC transfusion depends on cause of anemia & patient’s overall condition
Basic Chemistry Panel
Predominant electrolytes measured in lab:
Total CO2 / bicarbonate (bicarb)
Excretion of renal-mediated waste products is included in panel : Creatine (Cr) & blood urea nitrogen (BUN).
More comprehensive metabolic panel would include: Magnesium, Phosphorus, Calcium
1. glucose (GL)
4. Sodium (Na+)