Infection control protocols are in place to prevent as much harm as possible.
First, your title is inaccurate
Hospital says their blood test caused sepsis.
You misinterpreted what they said. I will explain contamination more thoroughly below, but additionally, bacteria in the blood stream (bacteremia) and Sepsis are not the same thing. You get a transisent bacteremia just brushing your teeth, but you don't get sepsis from it (except in rare rare circumstances).
Second, I will preface this by saying that by explaining why medical errors happen doesn't justify them. My opinion (and to qualify my opinion, I've spent months of my training in infection control quality improvement) is that infection control is an area in which we have a lot of work to do, as there remain many unacceptable events and outcomes, and failings occur at all steps in the processes. But that's another discussion.
Third, adverse events like lab errors, contamination, medical errors, hospital acquired infections, etc are generally tracked by hospital committees like Infection Control. I'm not sure if contaminated vials are always watched, but I have seen them discussed in such committees.
Fourth, I will address contamination.
Contamination of blood cultures does happen sometimes. It results
when a small amount of normal skin bacteria is pushed into the vials
when blood is added to the vials, making it unclear whether it was in
the blood to begin with. It can happen at the needle insertion or at
the hub insertion into the bottle diaphragm.
In a blood culture, low levels of a normal skin bacteria is usually a
flag for clinicians to suspect contamination rather than actual
In that case, depending on our suspicion for bacteremia, the severity
of the patient's condition, and condition-specific recommendations,
we might repeat it to ensure it was contamination. But we may, based on clinical picture, decide that the likelihood is so low that there is no benefit to repeating the test.
Is bacteria introduced into the bloodstream? Does that mean the patient now has bacteremia or sepsis?
- If the point of bacteria contamination was during needle insertion
into the skin, then yes some bacteria was likely introduced to the
patient's blood stream at that time. That would most likely be a
very, very small amount of bacteria; nonetheless, it is not entirely
impossible to get an infection from that. (After all, blood
infections and endocarditis can result from reusing IV drug needles,
right?) But bloodstream infections from venipunctures in hospitals is not common. (I will try to find some specific stats on that.)
- When you brush your teeth, you are pushing oral bacteria into your bloodstream, and have a transient bacteremia that your body eliminates and you never know it happened.
If it was just present on the diaphragm of the culture
bottle, then no it was not introduced to the blood stream.
It does not mean the bacteria was pushed into the bloodstream and
then infected blood was drawn out. The bacteria hitched a ride on
the blood flowing into the bottle, somewhere along the way.
Now to answer directly, yes this only happens when proper infection control protocols are broken. There are many reasons this might occur.
And yes, sometimes this is due to people forgetting or being careless.
Healthcare providers are always busy and sometimes rushed; being humans, that is when errors are more likely to occur.
But another very important reason to understand, sometimes it is due to the system or environment or equipment not being set up for success. Swiss cheese model of medical errors is a very interesting concept, I recommend looking it up.
Sometimes it is due to emergency speed of the test and protocol steps are knowingly hasty or skipped. If it is about saving a life, the route of least harm is often chosen.
Sometimes if a vein cannot easily be located, the skin needs to be touched to find an accurate site, and they may not have used a sterile glove to do so or reswabbed.
Your question of whether this was a serious breech of protocol is unfortunately subjective. It all depends on your expectations for human errors/attention/neglect/memory and system errors... and would be a great discussion on PhilosophySE perhaps. My expectations are perhaps higher than most, and these sort of things upset me, which is why I'm in administrative positions doing things about it.
But the question of whether this is not all that uncommon can be answered: correct, it is not uncommon.
Would the hospital consider this a serious breech of protocol? Not likely, although it may be tracked like other errors.
But I do not think it is inappropriate to bring your concern about contamination to the hospital, actually. Reminding them and encouraging raising standards is important, IMHO.
All this said, if she feels sick or develops a fever, regardless of what they said, she should be re-evaluated by a clinician to say whether anything more should be done. Hopefully this is all in the past at this point.