This process may also be used therapeutically to treat disorders resulting in extraordinarily high platelet counts such as essential thrombocytosis.

Platelet transfusions are traditionally given to patients undergoing chemotherapy for leukemia, multiple myeloma, those with aplastic anemia, AIDS, hypersplenism, idiopathic thrombocytopenic purpura (ITP), sepsis, bone marrow transplant, radiation treatment, organ transplant or surgeries such as cardiopulmonary bypass.

[citation needed] In adults, platelets are recommended in those who have levels less than 10,000/μL, or less than 20,000/μL if a central venous catheter is being placed, or less than 50,000/μL if a lumbar puncture or major surgery is required.

[citation needed] Collecting the platelets from a single donor also simplifies human leukocyte antigen (HLA) matching, which improves the chance of a successful transfusion.

[citation needed] Plateletpheresis products are also easier to test for bacterial contamination, a leading cause of transfusion-associated deaths.

If indicated, transfusions (one thrombapheresis concentrate) should be given until recovery of platelet function, generally approximately twice weekly.

The number of transfusions may be reduced if these patients are given recombinant human factor VIIa[medical citation needed] since the underlying cause are antibodies to platelet glycoproteins IIb/IIIa.

Some centers are experimenting with seven-day platelets, but this requires additional testing and the lack of any preservative solutions means that the product is far more effective when fresh.

Due to their higher relative density, white blood cells are collected as an unwanted component with the platelets.

If all of the incidentally collected white blood cells are transfused with the platelets, substantial rejection problems can occur.

It takes a trained person about 10 minutes to assemble the equipment, and this is not the safest or most efficient means of filtration because living white blood cells can release cytokines during storage and dead white blood cells can break up into smaller fragments that can still stimulate a dangerous response from the immune system.

In addition, simple filtration can lead to increased risks of infection and loss of valuable platelets.

A dose of single-donor platelets prepared using latest filters can contain as little as 5×106 white blood cells.

Most newer apheresis machines can separate a maximum donation of platelets in about 60 to 120 minutes depending on the donor's health condition.

The process takes about one to two hours while blood is pulled into the machine, mixed with an anticoagulant such as sodium citrate, spun around, and returned to the donor.

Unusually low calcium can cause more serious problems such as fainting, nerve irritation[citation needed] and short-duration tetany.

Such an acute hypocalcaemia is usually due to low calcium levels prior to donation, aggravated by the anticoagulant.

Hypocalcaemia can be curtailed by modestly increasing dietary calcium intake in the days prior to donation.

Serious problems are extremely rare, but apheresis donors are typically not allowed to sleep during the long donation process so that they can be monitored.

Firstly, the donor must not take aspirin or other anti-platelet medications such as clopidogrel (Plavix) for anywhere from 36 to 72 hours prior to donation (guidelines vary by blood center).

Some blood centers also prohibit the taking of any non-steroidal anti-inflammatory drug (NSAID) for 36 hours prior.

Adverse conditions that can happen during a plateletpheresis donation are hypocalcemia, hematoma formation, and vasovagal reactions.

The risk of these conditions is normally reduced by pre-donation education of the donors and change of apheresis machine configuration.

While cosmetically it is virtually invisible, the scarring also occurs on the vein itself, making it harder to insert a needle on future occasions.

[citation needed] However, a study conducted by the University of Miami Department of Dermatology and Cutaneous Surgery in 1999 demonstrated no positive effect from the application of topical vitamin E.[7]