What kind of infection can a CBC find?

When a Dr. runs a CBC what can that tell them? Would Hiv or Hepatitis affect the count?

A CBC is a complete blood cell count, not a what-is-causing-this-infection-test. A CBC indicates infection. That's all.

If infection is present, the differential part of this blood test (Both are sometimes referred to as a CBC with "diff") gives a breakdown on the numbers of each type of white blood cell that was present in the sample. While different disorders affect the numbers differently and while certain specific numbers can suggest a number of disorders, this still doesn't diagnose a specific illness or specific microorganism. However, it can guide a physician in the right direction. This answers questions 1 & 2.

Foe question 3, HIV & hepatitis (any particular kind of hep????) are infections, therefore this has already been answered. With most infections, the white count will be elevated but with an HIV infection, the white cells may be depleted and the count low. This would guide your doctor to test for disorders known to cause this.

For hepatitis, if the infection is affecting hemoglobin or red cell counts, this will be reflected as a CBC measures red blood cell counts and hemoglobin. If you had symptoms of hepatitis or have had possible exposure to active hepatitis, you'd also have liver function tests run to either rule it out or diagnose it and your doctor might want to test for disorders known to affect hemoglobin & red cells.

A CBC reflects the white blood cell count, red blood cell count, hemoglobin, hematocrit, platelet count, MCV, MCH, MCHC, RDW, MPV and the white cell differential measures neutrohpils, lymphocytes, monocytes, eosinophils and basophils. These are all the types of white blood cells. In summary, a CBC result won't come back to the doctor with a red flag stating "this is the infection found: _____", but your labs will help guide your doctor in reaching a diagnosis.