For example, during pregnancy a womans RBC mass is normal but because of an increase in blood volume the hemoglobin and hematocrit are diluted and thus decreased. Another example would be bleeding where the RBC mass would decrease but the concentrations of hemoglobin and hematocrit initially remains normal until fluids shift from other areas of the body to the intravascular space.The anemia is also classified by severity into mild (110 g/L to normal), moderate (80 g/L to 110 g/L), and severe anemia (less than 80 g/L) in adults. Different values are used in pregnancy and children. Testing
Anemia is typically diagnosed on a complete blood count. Apart from reporting the number of red blood cells and the hemoglobin level, the automatic counters also measure the size of the red blood cells by flow cytometry, which is an important tool in distinguishing between the causes of anemia. Examination of a stained blood smear using a microscope can also be helpful, and it is sometimes a necessity in regions of the world where automated analysis is less accessible. A blood test will provide counts of white blood cells, red blood cells and platelets. If anemia appears, further tests may determine what type it is, and whether it has a serious cause. although of that, it is possible to refer to the genetic history and physical diagnosis. These tests may include:

complete blood count (CBC); a CBC is used to count the number of blood cells in a sample of the blood.
One way to distinguish between the herpes virus (and hence herpetic gingivostomatitis) and varicella virus is by direct immunohistochemistry using fluorescent antibodies. Differential diagnosis
Diagnosis of HG is very much clinically based. Therefore, it is imperative to rule out other diseases that present similarly, bearing in mind the past medical history of the patient. Some differential diagnoses to bear in mind when considering herpetic gingivostomatitis are:

Teething in infants:  A study mentioned that  "primary  tooth  eruption begins  at  about the  time that  infants  are  losing  maternal antibody protection  against  the  herpes  virus. Also, reports  on  teething  difficulties  have  recorded  symptoms  which  are  remarkably  consistent  with  primary oral  herpetic  infection  such as  fever,  irritability,  sleeplessness,  and difficulty  with eating." Another study highlighted that "younger infants  with  higher residual  levels  of  antibodies  would experience  milder infections  and  these  would be  more likely  to  go unrecognized  or  be  dismissed  as  teething  difficulty." Herpangina: It is a disease that is caused by the Coxackie A virus rather than a herpes virus. In herpangina, ulcers are usually isolated to the soft palate and anterior pillar of the mouth.