What a CBC measures
A complete blood count measures the three kinds of cells in your blood: red cells that carry oxygen, white cells that fight infection and platelets that help blood clot. MedlinePlus describes it as one of the most commonly ordered lab tests, used to look for anemia, infection, bleeding problems and the effects of medicines.
The report can run to a long list of lines. Most of them are calculations from the same few measurements, which is why reading them as groups makes more sense than reading them one by one.
The red cell lines
The red cell section shows how much oxygen-carrying capacity you have and what your red cells look like. The ranges below are MedlinePlus examples for adult men; your lab’s printed range is the one that applies to you.
| Line | What it means | Typical adult male range |
|---|---|---|
| RBC count | Number of red cells | 4.6 to 6.2 million cells/mcL |
| Hemoglobin | Oxygen-carrying protein | 13 to 18 g/dL |
| Hematocrit | Share of blood volume that is red cells | 40% to 55% |
| MCV | Average red cell size | 80 to 100 fL |
| MCH | Hemoglobin per cell | 27 to 32 pg |
| MCHC | Hemoglobin concentration in cells | 32 to 36 g/dL |
| RDW | How much cell size varies | Lab-specific |
High hemoglobin and hematocrit can come from dehydration, smoking, living at altitude, lung or heart disease that lowers oxygen, and testosterone use. Low values mean anemia, which in an adult man always needs an explanation; our page on low hemoglobin in men covers the workup, and the hematocrit test has its own guide.
MCV and RDW: size and spread
MCV tells you the average size of your red cells, and RDW tells you how much they differ from one another. MedlinePlus explains that healthy red cells are about the same size, so a high RDW means a mix of large and small cells, and that RDW is read together with the other indices rather than on its own.
Small cells (low MCV) raise the question of iron deficiency or an inherited trait such as thalassemia. Large cells (high MCV) point toward low vitamin B12 or folate, certain medicines or liver disease. If your MCV runs high, the vitamin B12 blood test is a common next step.
White cells and platelets
The white cell count is a snapshot of your immune system. MedlinePlus gives a normal range of 4,500 to 11,000 cells per microliter. Infection, inflammation, steroid medicines, intense stress and cigarette smoking raise it, while viral illness, some medicines and marrow problems lower it. A mildly low count can also be a harmless inherited trait that is not uncommon in men of African descent.
A “differential” splits the total into neutrophils, lymphocytes, monocytes, eosinophils and basophils, each pointing to different problems. Platelets normally number 150,000 to 400,000 per microliter. A high count can follow bleeding or iron deficiency, and a low count can come from an enlarged spleen, marrow problems or some medicines.
Why every testosterone pre-screen includes a CBC
A CBC is required before testosterone therapy because testosterone stimulates red cell production. The Endocrine Society guideline describes a dose-dependent rise in hemoglobin on treatment, larger in older men, and treats a baseline hematocrit above 48%, or above 50% for men living at high altitude, as a relative reason not to start.
The same guideline asks for hematocrit at baseline, again at 3 to 6 months and then yearly, and advises stopping treatment if it climbs above 54% until it falls to a safe level. Without a pre-treatment CBC, there is nothing to measure that rise against. The CBC can also work in the other direction: the guideline lists mild unexplained anemia as one of the findings that can prompt a testosterone check in the first place.
How to prepare for a CBC
A CBC needs no fasting and very little preparation. Drink water normally, since dehydration can concentrate red cells and nudge hemoglobin and hematocrit up. If you have had a fever, a recent infection or a blood donation in the past few weeks, mention it, because each can shift the counts.
How Ultimate Male reads your blood count
A CBC is one of the four tests in our TRT pre-screening panel, alongside total testosterone, estradiol and PSA, and it is drawn on site at San Gabriel or Downey with results in about 24 to 48 hours. Your provider reads the red cell, white cell and platelet sections together and flags anything that needs a repeat or a follow-up test before any treatment decision.
For men already on testosterone, the CBC becomes a regular checkpoint; our page on how often blood work is needed on TRT explains the rhythm. A CBC can also be ordered on its own or within a broader panel from our preventative blood testing options.
