Serum Electrolytes Laboratory Test

Serum Electrolytes:
Electrolytes are substances that become ions in solution and acquire the capacity to conduct electricity. Electrolytes are present in the human body, and the balance of the electrolytes in our bodies is essential for normal function of our cells and our organs. These ions are measured to assess renal (kidney), endocrine (glandular), and acid-base function, and are components of both renal function and comprehensive metabolic biochemistry profiles. Their importance lies in part with the serious consequences that follow from the relatively small changes that diseases or abnormal conditions may cause.

Common electrolytes that are measured by doctors with blood testing include sodium, potassium, chloride, and bicarbonate. The functions and normal range values for these electrolytes are described below.

Specimen: venous blood
Pretest/Intratest/Post-test- same
Commonly ordered:
Sodium- 135-145 mEq/L
Potassium- 3.5-5.0 mEq/L
Chloride- 95-105 mEq/L

Sodium (Na+)
Sodium is primarily responsible for maintaining osmotic pressure. It maintains intracellular and extracellular fluid levels in the body. An increased serum sodium is present in states of dehydration as a result of diarrhea or vomiting. Low sodium levels usually are a result of too much water in the body.
Potassium (K+)
Potassium is a major component in cardiac function. Even small changes in Potassium can cause abnormal cardiac arrhythmias, affecting cardiac function. Too much potassium in the blood is usually caused by poor kidney function and can cause abnormal and sometimes fatal abnormalities in the heart rhythm. Low potassium levels are usually the result of potassium loss from excessive urination or from vomiting. A potassium level that is too low can cause abnormal heart rhythms.
Chloride (Cl-)
In combination with sodium, chloride maintains fluid levels by regulating osmotic pressure in the blood. An elevated chloride usually results from abnormal kidney function. A chloride level below normal usually results from excessive vomiting or diarrhea.

Complete Blood Count (CBC)

 

The CBC is used as a broad screening test to check for such disorders as anemia, infection, and many other diseases. It is actually a panel of tests that examines different parts of the blood.

• Red blood cells: The CBC's measurements of red blood cell (RBC) count, hemoglobin (the oxygen-carrying protein in RBCs), and mean (red) cell volume (MCV) provides information about the RBCs, which carry oxygen from the lungs to the rest of the body. These measurements are usually done to test for anemia, a common condition that occurs when the body has insufficient red blood cells.
• White blood cells: The white blood cell (WBC) count measures the number of WBCs (also called leukocytes) in the blood. WBCs, which help the body fight infection, are bigger than red blood cells and there are far fewer of them in the bloodstream. An abnormal WBC count may indicate an infection, inflammation, or other stress in the body.
• Platelets: The smallest blood cells, platelets play an important role in blood clotting and the prevention of bleeding. When a blood vessel is damaged or cut, platelets clump together and plug the hole until the blood clots. If the platelet count is too low, a person can be in danger of bleeding in any part of the body.

Specimen: Venous blood

Pretest: obtain syringe, tourniquet, vial with appropriate anticoagulant
Intratest: Cubital vein commonly used for venipuncture
Post-test: direct pressure and observe for bleeding, label vial

 

Normal Values For CBC:
RBC (M) 4.7-6.1/ (F) 4.2-5.4
Hgb (M) 14-18 / (F) 12-16 mg/dl
Hct (M) 42-52 / (F) 33-47 %
WBC 5-10,000
Differential count
Neutrophils- 55- 70%
Lymphocytes- 20-40%
Monocytes- 2-5%
Eosinophils- 1-4%
Platelets 150,000-400,000

Blood Test

 

LABORATORY PROCEDURES:

 

Three Phases of Diagnostic Procedures:
1. Pretest - Client preparation
2. Intra-test - specimen collection and VS monitoring
3. Post-test - Monitoring and follow-up nursing care

 

Blood Test:

• CBC - Hemoglobin, Hematocrit, WBC, RBC and platelet
• Serum Electrolytes
• Arterial blood gases
• Blood Chemistry
• Drug and Hormone Assay