LABS to know for cellular regulation

Red Blood Cells (RBCs)

Normal Values: 3.6 – 5.4 x 106 cells/µL*

What is it actually measuring?: The number of cells per µL, gives no info on quality or age of the cells

What does the cell/ chemical/ substance in the body actually do?: Red blood cells are predominantly responsible for carrying oxygen throughout the body

What causes a low or a high number?

Can be low due to low iron, low androgens, cell loss/blood loss or dilution of blood (fluid overload)

High due to high cell production or concentrated sample (fluid deficit)

What results from a low or a high number?

low=Anemia=fatigue pallor,etc

high=Hyperemia

What does abnormal mean for the patient (Symptoms? Exam findings? Implications?)’

Anemia: fatigue, pallor, exercise intolerance, shortness of breath, and makes cyanosis hard to detect

Hyperemia: thick blood, slow-flowing blood, skin color changes, risk of intravascular makes cyanosis easy to detect

Hemoglobin (Hgb)

• What it measures: The amount of hemoglobin protein in the blood (grams per deciliter). Hemoglobin carries oxygen in red blood cells.

• Normal range: 12 – 17.4 g/dL (slightly higher in men, lower in women).

• What it does: Binds oxygen in the lungs → delivers it to tissues → carries carbon dioxide back to the lungs.

• Low causes: Anemia (iron deficiency, B12/folate deficiency, chronic kidney disease, blood loss, bone marrow suppression).

• High causes: Polycythemia vera, chronic hypoxia (COPD, high altitude, sleep apnea), dehydration (hemoconcentration).

• Implications:

  • Low (anemia): Fatigue, pallor, shortness of breath, tachycardia, dizziness.

  • High (polycythemia/hemoconcentration): Headaches, dizziness, hypertension, risk of blood clots.

Hematocrit (Hct)

• What it measures: The percentage of blood volume made up of red blood cells.

• Normal range: 36% – 48%.

• What it does: Reflects red cell mass compared to plasma volume. Often parallels Hgb.

• Low causes: Anemia, bleeding, nutritional deficiencies, bone marrow suppression, fluid overload.

• High causes: Polycythemia, chronic hypoxia, dehydration, burns.

• Implications:

  • Low: Weakness, fatigue, pallor, exercise intolerance.

  • High: Thickened blood → risk of clotting, stroke, heart attack.

White Blood Cells (WBCs)

• What it measures: Number of leukocytes in blood.

• Normal range: 4.5 – 10.5 × 10³ cells/mm³.

• What they do: Defend against infection, help in inflammation, immune response, allergy reactions.

• Low causes (leukopenia): Bone marrow failure, chemotherapy, radiation, autoimmune disease, viral infections (like HIV), certain meds.

• High causes (leukocytosis): Infection, inflammation, stress, corticosteroids, leukemia.

• Implications:

  • Low: Risk of infection, fevers may be blunted, neutropenic precautions often needed.

  • High: Signs of infection (fever, chills, pus, local inflammation), or concern for malignancy if very high/persistent.

Platelets (Plt)

• What it measures: Number of platelets per microliter of blood.

• Normal range: 140 – 400 × 10⁹/L (or 140k – 400k/µL).

• What they do: Key in clotting → form platelet plugs to stop bleeding, interact with clotting factors.

• Low causes (thrombocytopenia): Bone marrow suppression, aplastic anemia, chemotherapy, autoimmune destruction (ITP), liver disease, sepsis, meds (heparin-induced).

• High causes (thrombocytosis): Iron deficiency, infection/inflammation, splenectomy, myeloproliferative disorders.

• Implications:

  • Low: Risk of bleeding, petechiae, bruising, nosebleeds, GI/GU bleeding, risk of intracranial hemorrhage if very low (<20k).

  • High: Risk of clotting (DVT, PE, stroke), but if very high (>1 million), paradoxical bleeding can occur due to dysfunctional platelets.