Sunday, June 26, 2011

"Shine a light" (Musings on what we take for granted & shouldn't)

This month's blog is a 'twofer.' Both parts arose from reading the May issues of AABB's Transfusion and AABB News. The blog's title derives from a Rolling Stones ditty of the same name.

MUSING #1 - On detecting mom's antibodies in babes

The first musing was stimulated by
The paper shows something true about many, if not most, transfusion medicine policies, namely that they are not evidence-based.

During a long teaching career, I'd often discuss with medical laboratory science students that what we do is based on many things, but seldom evidence. Shaikh and Sloan's paper illustrates the point perfectly.

Students are routinely told that newborns do not produce detectable ABO antibodies until about four months of age and, if ABO antibodies (isohemagglutinins) are detected, they are of maternal origin. The corollary is that maternal ABO antibodies can be detected in newborns up to 4 months of age, with implications for transfusion compatibility.

For example, AABB Standards specify that neonates up to 4 months who are not group O require testing for maternal anti-A / anti-B in order to receive ABO-specific RBCs. Instead of testing, most transfusion services simply issue group O RBCs to infants up to 4 months of age.

Shaikh and Sloan's study of ~1309 infants showed that 6.4% of infants up to 1 month of age had detectable maternal isohemagglutinins, while no infants 2-4 months of age had them. The practical implication is that infants who are at least 2 months old can safely receive ABO-specific RBCs without testing for maternal anti-A or anti-B, thus freeing technologist time and increasing the supply of group O RBC.

How refreshing to see some of our long-held assumptions tested and revised based on evidence....

Rh immune globulin (RhIg)
Many other TM policies lack appropriate evidence. One of the classics is the guideline to inject RhIg into Rh negative females within 72 hours of delivering an Rh positive (or weak D positive) newborn.  Like many transfusion-related policies, administering RhIg within 72 hours of delivery arose by happenstance and was not based on evidence:

In the USA initial experiments with Rhig involved ‘volunteers’ from Sing Sing prison. ('volunteers' is used loosely since it is debatable that anyone in prison is truly a volunteer.) Male prisoners were injected with various volumes of D+ red cells and later given different doses of RhIg to see what prevented them from making anti-D. Because researchers were allowed in the prison only from Monday to Friday, there was a subgroup that got a red cell injection on Friday but only received RhIg on Monday. It was from this group that the 72 hour recommendation arose.
Fortunately, the 72 hour guideline for RhIg seems to work. Would 96 hrs. or another number of hrs. work just as well? We do not know.


Similar well established guidelines with minimal evidence include to

(i) Begin transfusion within 30 minutes of removing RBCs from a temperature-controlled environment (4oC refrigerator)

(ii) Complete transfusion of RBC within 4 hours of removing them from a temperature-controlled environment
.... and many similar guidelines.

My sense is that, if providing a specific number enhances patient safety and helps transfusion professionals rather than handcuffs them with impractical requirements, and, if historical guidelines seem to work, sticking with them makes sense.

Policies that offer simple specifics are especially prudent for staff who may lack the in-depth knowledge and experience often needed to assess individual cases. With increased hiring of casual and part-time staff (nursing and laboratory), increased use of generalist technologists rather than transfusion specialists, and physicians with little transfusion medicine education in charge of rural laboratories (and those ordering blood anywhere), simplified policies are needed and appropriate.

MUSING #2 - On spinning and valentines

Two items caught my eye in the May issue of AABB News:

(1) The Pall advertisement on p. 15 (Take a greener approach to whole blood processing) promotes its transfer bag for cryo pooling. The ad has a lovely photo of lily pads and a frog against a green backdrop but it struck me as spinning the meaning of green almost to what's known as greenwashing.

As elusive as greening is to define, it's generally considered to include a constellation of these practices:

  • Reduce consumption, especially reduce use of resources like water and fossil fuels
  • Transition to renewable energy sources
  • Reduce waste, particularly waste that's not biodegradable, eg., plastic bags
  • Minimize pollution
At its essence green means being friendly to the environment and protecting the pale blue dot for future generations.

More efficient use of a product like a plastic transfer bag (even allowing that Pall's transfer bag increases efficiency) doesn't necessarily equate with being green, except in the broadest sense, so as to make the term almost meaningless. The problem with misleading advertising, even when claims are inflated relatively benignly, is that such spinning undermines  customer confidence that the company is transparent in other areas.

(2) The second item was "Mergers and acquisitions on the manufacturing side," a priceless valentine to the manufacturers interviewed for the article (Haemonetics, CaridianBCT, Novartis Diagnostics). The industry reps who were interviewed (top brass like CEOs and VPs) were allowed to spin their mergers without comment and in the process smoothly managed to insert the benefits of their services and products.

According to the piece, in all cases it seems that mergers are good: (my comments in brackets)

  • Good for the companies (for their bottom lines due to goodies like economies of scale and bulk purchasing but always kumbaya-ville for the two corporate cultures - I doubt it)
  • Good for their employees (at least before staff are let go or vacant positions due to retirement,etc., are not filled forcing remaining staff to do more, often with less)
  • Good for customers (until less competition and more oligopolies influence pricing in favour of manufacturers. As an example, has the oligopoly of Immucor and Ortho Clinical Diagnostics, with their razor-blade business models, led to lower reagent prices? )
Mergers create oligopolies. Many outcomes are possible but one is that oligopolies drive prices up. Increased competition is supposed to be advantageous to consumers since it drives prices down and is a major rationale for the benefits of free enterprise. Less competition, by extension, is bad, especially for customers.

The AABB, by allowing industry's rosy win-win claims to go unchallenged and by publishing self-promoting descriptions of products, gave the companies thousands of dollars of free advertising. The organization depends on its industry advertisers, but that's quite the valentine, nonetheless.

The musical ending to this blog and the source of its title is the Rolling Stones' rock-gospel song:
It's worth noting that Shine a light was originally titled Get a line and was about the worsening drug addiction of then band member Brian Jones.

As to Shaikh and Sloan's research on how long mom's antibodies are detectable in babes, how about this Beatles classic?
And just for fun, to give the moon its due, one of my favorite songs:
As always, the views are mine alone. Comments are most welcome BUT, due to excessive spam, please e-mail me personally or use the address in the newsletter notice.