🩸CBC Crash Course: What You REALLY Need To Know For The ASCP

Greetings my Little Gang of Nasties😜😈

The Complete Blood Count (CBC) is one of the most common lab tests you’ll see, and it’s PACKED with useful info. Here’s a quick breakdown of the key components and how to think about them:

🩸WBC: White Blood Cell Count

Literal count of all white blood cells in circulation.

🩸RBC: Red Blood Cell Count

Literal count of all red blood cells in circulation.

🩸HGB: Hemoglobin

Oxygen-carrying protein in RBCs. Low in anemia, high in chronic heart/lung disease.

🩸HCT: Hematocrit

% of your blood made up of RBCs.

Low = anemia

High = dehydration, polycythemia

🩸MCV: Mean Corpuscular Volume

Average size of RBCs.

Microcytic (< 80 fL) - iron deficiency, thalassemia
Normocytic (80–100 fL) - acute blood loss, chronic disease
Macrocytic (> 100 fL) - B12/folate deficiency, liver disease

🩸MCH: Mean Corpuscular Hemoglobin

Average amount of HGB in ONE RBC.

🩸MCHC: Mean Corpuscular Hemoglobin Concentration

Average concentration of HGB in ALL RBCs.

Hypochromia if < 32 g/dL (iron deficiency anemia, thalassemia)

🩸RDW: Red Cell Distribution Width

Variation in RBC size.

>16% think anisocytosis (often means bone marrow is working hard, useful in anemia diagnosis)

🩸 PLT: Platelet Count

Number of platelets in circulation.

Low = bleeding risk

High = inflammation, iron deficiency, post-surgery

🩸MPV: Mean Platelet Volume

Average size of platelets.

Big = younger platelets (bone marrow active)

Small = older/fragmented platelets

💡 Study Tip: When reviewing CBC results for the ASCP, don’t just memorize definitions, practice linking each abnormal value to its possible causes. That’s what will help you crush both questions and real-life cases.

Hope this helps a bit - also check out the attached .pdf for a better chart!

-Marilyn

✨If you’re still struggling or feel lost with your ASCP Exam prep, let’s get you on track. Book a 1:1 call with me so we can assess your needs!

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