Blood and blood vessels – Lupus may lead to blood problems, including a reduced number of healthy red blood cells (anemia) and an increased risk of bleeding or blood clotting.

Source: https://www.kaieteurnewsonline.com/2023/05/28/lupus-an-autoimmune-disease/

But a higher number of white blood cells means there is 'less room' for other cells, including red blood cells - which transport oxygen around the body - and platelets - which cause blood to clot when the skin is cut.

Source: https://www.dailymail.co.uk/health/article-11644141/Doctors-wrongly-told-10-times-girl-3-fine-actually-leukaemia.html?ns_mchannel=rss&ns_campaign=1490&ito=1490

Copper is an essential mineral that plays a vital role in many bodily functions, including the production of red blood cells, the absorption of iron and the maintenance of nerve cells.

Source: https://www.lewrockwell.com/2023/03/joseph-mercola/are-these-the-19-most-important-supplements-to-take/

Diamond-Blackfan anemia, or DBA, is a genetic disorder in which the bone marrow is unable to produce red blood cells.

Source: https://abc7.com/friends-of-oliver-childrens-health-diamond-blackfan-anemia-research/13358874/

Does the fact that something performs complicated biochemical tasks and has a “lifespan”, like a red blood cell, imply life as distinct from the body it is part of?

Source: https://www.crikey.com.au/2023/03/17/bruce-lehrmann-defamation-federal-court-case/

FILE – This microscope photo provided on Oct. 25, 2023, by the Centers for Disease Control and Prevention shows crescent-shaped red blood cells from a sickle cell disease patient in 1972.

Source: https://www.dailybreeze.com/2023/11/16/the-worlds-first-gene-therapy-for-sickle-cell-disease-has-been-approved-in-britain/

In the same study, researchers conducted blood sampling of the dairy cattle exposed to wildfire smoke and found there was an increase in some white blood cells and a decrease in red blood cells and neutrophils.

Source: https://countryfolks.com/wildfire-smoke-impacts-on-livestock/

Plasma is a straw-colored liquid that is seen after centrifugation in the plasma donation procedure separates out blood cells such as red blood cells, white blood cells and platelets.

Source: https://www.prnewswire.com/news-releases/plasma-donors-needed-to-save-lives-301818595.html

Rectal bleeding with bright red blood.

Source: https://madamenoire.com/1350242/cancer-rates-are-climbing-among-women-and-young-adults-in-their-30s-according-to-a-new-study/

Sickle cell disease is the name for a group of inherited health conditions that affect the red blood cells.

Source: https://www.leicestermercury.co.uk/news/leicester-news/leicester-mother-done-having-kids-8521441

So, I will start with answer to your first part of the question regarding the fetal hemoglobin versus the number of red blood cells and all these.

Source: https://seekingalpha.com/article/4600640-editas-medicine-inc-edit-q1-2023-earnings-call-transcript?source=feed_all_articles

So you’re donating your blood, but in more than 50 days, all of the things that you lost, so the iron, the red blood cells, everything will be regenerated, and you’re back to normal,” Kazan said.

Source: https://www.mcgilltribune.com/student-life/preserving-life-drop-by-drop-03-14-2023/?utm_source=rss&utm_medium=rss&utm_campaign=preserving-life-drop-by-drop-03-14-2023

Vitamin B12 performs the job of producing red blood cells, and helps the brain cells function in the best possible way - it also aids in the production of myelin, which is what connects cells in the mind.

Source: https://www.dailyrecord.co.uk/lifestyle/health-fitness/exact-age-people-develop-vitamin-30775929

“Whole blood or anything that contains red blood cells must be packed with ice and maintained at a temperature between 2-8 degrees C. Platelets must be kept at 22 degrees, which is more or less room temperature.

Source: https://www.timesofisrael.com/israel-tests-drone-delivery-for-blood-and-other-critical-medical-supplies/