Editing Anemia (section)

===Testing===
Anemia is typically diagnosed on a [[complete blood count]]. Apart from reporting the number of [[red blood cell]]s and the hemoglobin level, the [[Automated analyser|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.{{cn|date=February 2024}}
{| class="wikitable"
|+ WHO's Hemoglobin thresholds used to define anemia<ref>{{cite book |author=World Health Organization |title=Worldwide prevalence of anaemia 1993–2005 |year=2008 |isbn=978-92-4-159665-7 |url=http://whqlibdoc.who.int/publications/2008/9789241596657_eng.pdf |access-date=2009-03-25 |publisher=World Health Organization |location=Geneva| archive-url= https://web.archive.org/web/20090312111339/http://whqlibdoc.who.int/publications/2008/9789241596657_eng.pdf| archive-date= 12 March 2009 <!--DASHBot-->|url-status = live}}</ref>
(1&nbsp;g/dL&nbsp;=&nbsp;0.6206&nbsp;mmol/L)
|-
! Age or gender group
! Hb threshold (g/dL)
! Hb threshold (mmol/L)
|-
| Children (0.5–5.0 yrs)
| 11.0
| 6.8
|-
| Children (5–12 yrs)
| 11.5
| 7.1
|-
| Teens (12–15 yrs)
| 12.0
| 7.4
|-
| Women, non-pregnant (>15yrs)
| 12.0
| 7.4
|-
| Women, pregnant
| 11.0
| 6.8
|-
| Men (>15yrs)
| 13.0
| 8.1
|}
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.<ref>{{cite web|title=Anemia|url=https://www.radiologyinfo.org/en/info/anemia|access-date=2021-10-11|website=Radiologyinfo.org|language=en}}</ref> These tests may also include [[Ferritin|serum ferritin]], [[Serum iron|iron studies]], [[Serum vitamin B12|vitamin B<sub>12</sub>]], genetic testing, and a [[Bone marrow examination|bone marrow sample]], if needed.<ref name=":2">{{cite web |title=How Anemia Is Diagnosed and Treated |url=https://www.webmd.com/a-to-z-guides/understanding-anemia-treatment |access-date=2021-10-11 |website=WebMD |language=en}}</ref><ref name=":3">{{cite web |title=Anemia Types, Treatment, Symptoms, Signs, Causes & Iron Deficiency |url=https://www.emedicinehealth.com/anemia/article_em.htm |access-date=2021-10-11 |website=eMedicineHealth |language=en}}</ref>

Reticulocyte counts, and the "kinetic" approach to anemia, have become more common than in the past in the large medical centers of the United States and some other wealthy nations, in part because some automatic counters now have the capacity to include reticulocyte counts. A [[reticulocyte]] count is a quantitative measure of the [[bone marrow]]'s production of new red blood cells. The [[reticulocyte production index]] is a calculation of the ratio between the level of anemia and the extent to which the reticulocyte count has risen in response. If the degree of anemia is significant, even a "normal" reticulocyte count actually may reflect an inadequate response.

If an automated count is not available, a reticulocyte count can be done manually following special staining of the blood film. In manual examination, activity of the bone marrow can also be gauged qualitatively by subtle changes in the numbers and the morphology of young RBCs by examination under a microscope. Newly formed RBCs are usually slightly larger than older RBCs and show polychromasia. Even where the source of blood loss is obvious, evaluation of [[erythropoiesis]] can help assess whether the bone marrow will be able to compensate for the loss and at what rate.

When the cause is not obvious, clinicians use other tests, such as: [[erythrocyte sedimentation rate|ESR]], serum iron, [[transferrin]], [[folate|RBC folate level]], [[hemoglobin electrophoresis]], [[renal function]] tests (e.g. [[serum creatinine]]) although the tests will depend on the clinical hypothesis that is being investigated.

When the diagnosis remains difficult, a [[bone marrow examination]] allows direct examination of the precursors to red cells, although is rarely used as is painful, invasive and is hence reserved for cases where severe pathology needs to be determined or excluded.{{medical citation needed|date=January 2016}}