Writing ‘historical’ articles from the moment of Rh discovery to current time has been fun. Along the way I’ve discovered the math does not add up. Basically this, the math or percentages is screwy and it can’t be right. Prove to me that 85% of the population is Rh + and 15% is Rh -. Please prove me wrong because I’d like to know how the numbers are derived. Now, I freely admit it’s possible my Rh negative blood is what compels me to find ‘source’ documents, because I’d love to just insert all the familiar numbers and percentages of ABO and Rh types quoted here and there and be done. I can’t. It’s like asking me to pull my eyelashes out and hey, I’m not even a math lover. So what the heck am I talking about? Statistics should move up and down over the years, but ABO and Rh tables stay the same.(85/15)
Here’s the problem in a nutshell. I surmised that in order to put information on ABO and Rh into statistical tables there must be a place that logs in the ABO and Rh of each baby born in the US. You agree? Of course you do, but the data is no longer being captured or put in any public data bases. Not the CDC, not State Public Health Departments, and not the National Newborn Screening Bank. Now, I know way more about newborn babies and their diseases than I ever wanted to know, but heck, no ABO or Rh groups are recorded. I know what day of the week most are born in, I know the % of smoking moms, I know the % of mom’s getting full prenatal care, but no data on ABO and Rh.
As an Rh negative mother, I learned my children’s ABO group and Rh at birth. Other mothers aren’t given the information. That shocked me because I knew the hospital labs ran ABO and Rh on cord blood. So I set out to find where the information would be, only to learn this. Of the 4 hospitals in my area, 3 had stopped running ABO and Rh on newborns and the 4th would stop in 2014. Look, to be honest, my state is the very last state to jump on a new trend, so if Alabama is doing it, you can be assured other states haven’t been running ABO and Rh for years! No more cord blood typing, and I suppose this must be a huge cost savings to hospitals.
I contacted science-like places on the Internet posting blood group tables and percentage stats to ask for source documents. None had them. Silly me, I thought the data were being generated by numbers in real time and based on the annual birthrate and corrected as birthrates dropped and immigrants came in. Not happening folks…sorry. Which means all the tables that don’t cite the source are invalid. I should thank or curse Dr. Ralph who pounded the idea home in my masters thesis: Don’t use data without a scientific source.
My title may be misleading, but I’m hopeful someone will read this article and send me source data! CDC doesn’t keep the national ABO and RH group data for the US. But I did learn one interesting statistic from CDC. Rh sensitization rate was last recorded in 2002 in their National Vital Statistics Report (note the link and check Table 26 page 67). CDC said as of 2003 Rh sensitization rates were no longer recorded. I was told the disease that had a 50% death rate back in the 1940s is now statistically insignificant. So, while this data is 11 years old it’s based on actual reports and is the last year data is available. I crunched the stats and here is the only math I have for Rh+ babies born to Rh – mothers in 2002 (called Rh sensitization). Try to guess what the percentage is before reading.
Live Birthrate in 2002 – 4,021, 726
*One state wasn’t required to report and others didn’t report consistent data on Rh sensitization.
Stats derived from 3,982, 314 completed records.
2002 Rh sensitization rate total 26, 648
Whites 24, 227 or .67% …Blacks 1,881 or .05% …Other 540 or .01%…
So what is the big deal other than people display math tables on ABO and Rh groups without a source? Well, if we don’t know the ABO and Rh groups in the US how will we ever know if say O negative blood or AB negative blood drops significantly in the population? How do we know Rh negative blood is still the minority at 15% and not 45%? The 15/85% may have been true in 1901, but even then the scientists tested small amounts of people. How strange that here we are in 2013 sputtering out the same numbers like robots. Where’s the math?
I’m a busy writer but I honestly tried to find the answers. Even searches on science engines didn’t reveal a public data base. If you have the source, set me straight!
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