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CADs Having Trouble with RBC/CBC Blood Testing

As a CAD, you may find there is a disconnect in the medical community between Professional Blood testing facilities/personnel, and CAD (Cold Agglutinin Disease) Patient blood testing requirements.

You may even deal with conflict concerning your doctor over this subject.  Especially if they are not up to speed with CAD.  Or have never had a CAD patient that the agglutination present, during standard protocol blood testing, fails to result a CBC/RBC.

The more CAD Cold Sensitive/Reactive you are, the more this conflict will arise.

Many doctors or Blood Testing Facilities may not have dealt with a CAD patient, or a CAD patient that has moved through various severity or cold sensitivity stages of the disease.  They may not have found the need to come up to speed concerning issues with patients that have become more “cold” sensitive.

Link to Printable Phlebotomist – Lab advisory.

This cold sensitivity can change for CADs as time goes on.  Meaning; they become reactive to temperature that is less cold than what used to “affect” them.  By affect we mean, both visual physical CAD symptoms , as well as non visual symptoms, of agglutination and Hemolysis.

Hemolysis kicks in even if the CAD patient is unaware.   CAD reactivity happening at a cellular level within the blood.  The reaction is often not about feeling cold, or feeling any type of pain or discomfort.  Not always about seeing a visual physical indicator the body might reveal.

A CAD’s primary line of defense in preventing Hemolysis, is to be vigilant about remaining warm at ALL times.  Don’t wait until you think you need to do it.  Don’t wait until you are dealing with visual symptoms.

We talk more in depth below,  about what “stages” mean to many CADs.

There may be a lucky group of CADs that have low level cold sensitivity?  Some CADs, in which their condition remains static at that low level?  They may lead a normal life and seem unaffected by the varying temperatures around them.  They may not even be aware they have CAD?  No physical symptoms to ever make them question anything.  It might only pop up on a blood test.

For the most part we aren’t hearing that scenario.  At least not in our social media support group, or CADs that contact us direct.   But that might simply mean, the more severely affected CAD’s out there, are the ones searching for information?

This article or webpage specifically pertains to when CBC/RBC blood tests start failing to result properly.  When standard blood testing protocols start becoming an issue for the CAD patient.

One of our first conflict started when labs started indicating they had to reheat the sample to result the RBC/CBC.   Results at that point became hit and miss.

While many other routine blood tests are unaffected.

Some of the tests that seem to fail , if “Keep it Warm Techniques” are not followed are listed below.  Depending on the CAD patient.  RBC/CBC is a definite unless they are mildly cold sensitive (agglutination triggering cold).

The other tests may or may not be true.  This is from feedback from numerous CAD’s.

RBC/CBC  (Known for sure)
Thermal Amplitude Blood Test.
Cold Agglutinin Titer
Immunoglobulin quantification
Immune fixation
Flow Cytometry (Bone Marrow Aspirate)

The focus of this article is not about the disease itself.  Not about the different severity stages a CAD may experience concerning their health.  But about the problems a CAD will most likely encounter at some point, having a common RBC/CBC  blood test done.

If you are new to CAD in general, you may also want to go to our page I was just informed I have CAD.  Now What?

Ironically the (CBC/RBC) test.  The specific blood test a CAD Patient needs to monitor their Red Blood Count/Hemoglobin levels,  and monitor to see if they are falling to anemic levels.  Is the very test that can fail to result, or result with inaccurate numbers.  Inaccurate numbers can lead to an unnecessary scare or perhaps unnecessary treatments if someone doesn’t question perhaps erroneous numbers, and have the test re-run.

It seems the worse your CAD sensitivity becomes [more sensitive and reactive to the cold, or more agglutination].  Perhaps evident by the higher your Titer ratio, the more standard Blood drawing/testing protocols for the CBC/RBC, cease to provide a result, or an accurate result.

You as a CAD may experience 3 stages of blood testing problems or not.   3 Phases, a scale of 1 to 3,  distinct categories, degree of severity, a progression from something to something distinctly different?  From something that worked one way, but not longer works now.

Or whatever Key word, or phrase you deem might be an appropriate way of labeling the change in Blood Testing process requirements.  Basically, process changes required to produce an accurate RBC/CBC for a CAD patient.  Depending on how cold reactive their blood is.

We want to clarify this because a select few want to split hairs on this subject, or the label we use.  Often commenting on social media there is no “progression” with CAD.  They indicate “stages” is non existent, or an inappropriate label.

While others that have similar CAD experiences, fully recognize and understand the concept we are attempting to communicate.  All in an attempt to get you an accurate CBC/RBC, without frustrating multiple blood draws.  All because the test does not result, or worse, comes back with erroneous low numbers.

If you are one of the lucky ones that are static at a low level, and not experiencing any difficulties with blood testing [RBC/CBC].  Consider yourself lucky.  Just don’t muddy up the waters for others experiencing difficulties and needing answers to get accurate CBC/RBC tests.  All CADs are not the same.

Please do not interject on social media, there are not different levels, stages, or some apparent progression.  If you feel there isn’t, you are one of the lucky, less affected and truly don’t know what you are talking about.  Contradicting the term/label used at this point, or what we are attempting to communicate here, only serves to confuse people really needing this info.

To be clear.  To our knowledge, there is not an official CAD related medical term to define what we are attempting to share here with other CADs.   If there is, please email us that info, the source, and the sources credentials.  [This was originally posted 2019 – To date we have had zero sources provide any official contradiction or edit to the terms currently used here]

For the sake of conversation and explanation, we are simply using the term STAGE, as our label.  This is not a term from the medical community so don’t expect to approach your Doctor or Phlebotomist and start throwing this term at them.  You will have to explain further.  You will also have to be armed with some knowledge to make yourself credible.

Since there is no official medical term established by the medical community for this CAD scenario (as of writing 2016).  We have found, about the time we label it ABC, someone on social media starts commenting it should be labeled XYZ.  This has been going on for a few years.  We can’t satisfy everyone.

Please accept these testing concepts for what they are.  Until such time the medical community might define, document this, and establish some standards and alternate protocols for the more cold sensitive CAD’s.

Bear with us while we attempt to explain this further.

So let us define first.   We are using the Webster Dictionary where their definition of “stages” is:

a single step or degree in a process; a particular phase, period, position, etc., in a process, development, or series.

The term/word “Stages” seems to apply perfectly.

STAGE = Our label to explain testing differences & change in lab processing

“Stage” in this case defines; a different approach that must be taken to test a CAD patients blood for a CBC/RBC.  When a  CADs Cold Sensitivity becomes more elevated or severe.  When Agglutination (Red Cells binding together or clumping occurs) happens at high and higher temperatures.  Some change in the CAD patients blood, that causes an existing working blood testing method, to start consistently failing and some other testing method is necessary.

This pertains to blood testing, not the disease itself.   Though, as the RBC/CBC blood testing protocol necessitates a change in testing method.  The CAD patient has most likely become more sensitive or more reactive to the cold.  Whether they are aware of the change or not.  So there does seem to be some type of relationship one could make.

So “stage” may also roughly represent the sensitivity level a CAD is at?

Stage 1 Minor.

Stage 2 Severe.

Stage 3 Acute.

But again, this webpage is trying to focus on Testing, not the Disease.  But it quickly becomes apparent these two subjects are intertwined.

For the RBC/CBC test processes, there appears to be a scale from 1 to 3.  Or 3 stages.  Or what known parameters impacts the test and causes it to fail.  Is there a stage beyond that?  Some 4th way of testing that might be needed?  Not to our knowledge.

This might apply to other blood tests?  But for the most part it seems to only affect the CBC/RBC,  Thermal Amplitude Blood Test, and the handful of other tests previously stated. This is based on personal experience as well as input from many CADs, over many years (decades at this point), and several reliable reference sources.   We will update this article if numerous people report problems with other tests.

So remember, this is only a guide for those that are finding their CBC/RBC Tests seems to fail.

“Standard Protocol”  is always successful

During the early stage, or least amount of Cold Sensitivity, a CAD experiences. Standard Protocol blood draws & testing methods work fine and produce usable RBC/CBC test results.  This is the method that a lab uses on all normal (non-CAD) people.  Nothing special is done.  They can ship the blood sample off to be processed at another location.

Samples can be drawn at a satellite facility, held, shipped, and later tested without special handling.  The lab can simply reheat the sample to obtain an accurate result.  No issues with resulting properly….at least with normal patients…even some low level CAD patients.

Note:  A Satellite Facility is a blood collection point where there is no lab processing.   It could be the Drs office or a facility location associated with a lab at another location.  The collected blood sample is either mailed or courier shipped to a blood lab at another location.  More exotic testing is often done at more centralized and specialized labs, at far off locations. 

In this Standard Protocol testing stage.  The lab can get good a RBC/CBC.  It won’t fail.  You will never know  anything different unless the lab notates some type of agglutination seen.

In this stage, Standard Protocol uses no “Keep it Warm” techniques on the drawn blood sample. (“Keep it Warm Technique” – see stage 2)

Rewarming your specimen at the lab, to perform the test, may be successful.  A process you as a patient may never know goes on.

Though lab notes on your test results may state something like “Cold Agglutinin Detected”, “High levels of Agglutinin”, or “Clumping observed due to Agglutinins”. The CBC/RBC may still result accurately during this first Standard Protocol stage.

Note:  People that donate blood at times, will receive a notice about high or abnormal Agglutinins being identified.

Since Agglutinins may be low level, there may have been no warning from other notable physical symptoms.  You might not be Anemic to any degree.

This type of notice is often a shock to the donor since a previous donation went un-noticed, or not notated.  Especially when they start searching on what “agglutination” means.

Dr. follow-up is recommended.  We further suggest you keep your own copies of blood test results from this point forward.  If you can obtain a previous test result that was OK it would be beneficial to have those for a baseline reference later.  Also it is wise to document any changes that transpired, health wise, from a previous good RBC/CBC, to one notating “Agglutinins”.

It is possible this is a temporary condition that will pass with time?


“Keep it Warm” Techniques necessary

CADs that have become more Reactive to cold Temperatures than a stage 1  CAD.  We are grouping these CAD together as stage 2..

In this group the Standard Protocol CBC/RBC Tests may start failing often, or fail all the time.

Initially the patient may experience hit and miss CBC/RBC tests that fail or are inaccurate.  Where you as a patient have to give another sample and they test again.  You may not suspect what is going on yet.  Not tie it to the possibility you are becoming more cold sensitive.  Your Dr may not even be aware, let alone the facility you are being tested through.

If you have moved into this group of CADs.  The blood specimen will start requiring special handling to produce consistent, accurate test results.

CADs, in this Stage 2 group, may eventually require a “Keep it Warm” process performed all the time.

The specimen tubes must be pre-warmed, the drawn specimen kept warm, and the lab testing done “stat”.   Ideally at body temperature 98.6°F/37°C.

Your particular Medical Care Providers, Phlebotomist, and or lab, may or may not be up to speed on any of this?  In our experience even into 2021, this seems to be an on-going hassle.

Satellite specimen collection where the sample is later shipped to a lab, reheated at the lab later, will not successfully result for the CBC/RBC in most of the stage 2 CADs.

We must mention; “keep it warm” is another CAD Patient made up term used by many CADs.  But to our knowledge it is certainly not an official medical term.  So if you start throwing that term around at a blood testing facility or ER room, you might encounter a blank stare.   You will  have to explain.  Expect to be met with doubt.  Having written documents explaining this from your Hematologist, is really necessary.  Or at least most helpful.

This “Keep it Warm” technique will often be talked about or recommended on CAD types of social media or support forums.  Perhaps your doctor will  know enough to advise you?  If they are familiar with CAD, they will most likely explain this to you.  If they are aware they hopefully give you written instructions to present at your blood draws/testing…..especially for any CBC/RBC.  If not, request it.

Once you are in this stage 2 scenario.  It’s best to have written and signed documentation (By your Dr on their letterhead) detailing the steps to the “keep it warm” technique.  Carry this with you to present at any blood facility, ER Room etc.  Believe me, it will prove invaluable to you.  It will prevent lots of conflicts or even being disbelieved, looked at as a problem person, etc.  Ultimately the goal is, it will eliminate multiple arm poking for re-doing the test.  To also get you an accurate result!

When this “Keep it Warm” process is not followed on a CAD at this cold sensitivity level.  The CBC/RBC will often fail to result, or have invalid numbers.

Note:  Often patients newly identified as having CAD, are already in this stage.


“Plasma/Saline Replacement” Technique necessary

Some CADs become even more sensitive and reactionary to the cold, than the “Keep it Warm” group.

But this is extremely rare.

We group the CADs that are so cold sensitive, that “Keep it Warm” techniques fail to product a good RBC/CBC, into a group we term Stage 3.

In these CADs, the clumping/agglutination of the blood may occur even using “keep it warm” testing techniques.  Meaning the “Keep it warm” techniques will eventually start failing for some CADs.

This problem seems to apply to an even smaller percentage of those with CAD.  So this very small percentage of CADs are truly rare indeed. Just hope you don’t have to deal with this.

Our observation of this change occurred about 16 years after the disease was first diagnosed.   As with anything CAD related, this time line is probably all over the place from individual CAD, to CAD.  It is very well possible many CADs  will never get to this sensitivity level?

For these even more rare CAD patients, in this 3rd stage. Some have to seek out a  facility that is willing to use a Plasma/Saline Replacement Process to produce successful and accurate CBC/RBC results.

Most labs seem reluctant to accommodate in this manner.  The process is documented at the bottom of this article.  It is definitely not Standard Protocol.  In many cases it will take written documentation from a Dr willing to take the time, a Lab willing to accommodate, and often times approvals, waivers, or involvement of some type from your insurance provider(s) so they pay for the procedure.

The documentation we present below is not worded by us,  or by another lay person.  Its not our opinion.

It was written by a medical professional.  The lab manager of a major hospital.  When Marilyn could no longer have her RBC/CBC run using the “keep it warm” techniques.  It was their solution for doing her RBC/CBC when she was admitted to the Emergency Room and eventually ICU for a couple of weeks.

In our personal case this was triggered when Marilyn’s blood continuously failed to result using the stage 2 “keep it warm” techniques, time after time.

Around the same time Quest, LabCorp, and CPL, (Blood Testing Labs – USA) all starting telling Marilyn they could no longer test her RBC/CBC.  Up until that point they too were successful if they used the “keep it warm” technique.

In Marilyn’s case, her Hematologist had to set up a special account for her at another local hospital.  A facility that normally does not do “Out Patient” type services.  That hospital was willing to make special arrangements for the testing, and the abnormal billing as an outpatient, that satisfied your insurance carrier requirements.

Even then, Marilyn always calls ahead and touches base with a lab contact so they get a heads up she is coming in.  Every time specific personnel change, problems arise.


Once you identify you are truly a CAD patient, you need to be better informed. Educate yourself, and actively be involved to ensure your Doctor, Phlebotomist, and Lab are all on board with the differences in testing.  Know what “stage” you are in.  Know what is required, so you can speak up for yourself.  If you are well informed , you may know more about CAD, than the medical professional facing you.  Some freely admit it, others don’t.

At the same time, you don’t want to get all upset and demanding “keep it warm” techniques, if you are in the stage 1 arena.  Or you are having non-CBC/RBC tests run.  If you start insisting on “keep it warm” techniques when not necessary.  That will only confuse things and ruin your credibility with the medical staff.

Consider yourself lucky, the longer you remain in the group of stage 1 CAD’s.  But quite frankly the bulk of CAD’s seem to be in the Stage 2 group.

Once you know you have moved into the second stage, many CAD patients, on their own, attempt to work with their blood testing facilities.  Making attempts to educate those they come into contact with.

Many have found help from other CAD Patients that have blazed the trail and provided information.  Having printed material along with you certainly helps.  Again, written instructions from your doctor is the best way to go.

If your requirements are written by your doctor on their letterhead, so much the better.  This is truly the way to approach this and the medical people treating you that may not know your history, or have any knowledge of CAD.  This is a must have for any Emergency Room type of visit.

If it is a facility that has dealt with other CAD patients, feel fortunate.  Everything might simply be routine for them.

There is also a big problem with CAD patients that encounter new facilities or medical personnel.   Such as being transported to an ER room, treated by First Responders, etc.  Often they will admit they have no knowledge of CAD.

COLD IV Fluid Infusions – A hazard for the more reactive CADs

Many CAD patients (depends on the CADs temperature sensitivity) always need most IV infused fluids run through a warmer. i.e. Blood Transfusions, Saline, etc.  Ideally through a Blood Warmer at 37°C.

Other lesser effective techniques can be used.  Prewarming the IV bags.  We have seen them warmed in hot water various ways.

Or heat packs, or heating pads, applied to the site of the infusion and directly above on the arm.

Marilyn is going through chemo treatment (First quarter 2021).  The facility has no blood warming machines.  They do pre-warm all her IV’s.  She carries an IR Temperature gun.  As long as they get it to above 85°F/29°C she has had no problems.  They actually ask her to double check them before they are infused.   She is highly CAD reactive.  To the point any CBC/RBC Blood Test must use the Plasma/Saline Replacement process.

Get the doctor treating your CAD to put this in writing on a document you carry at all times.  Don’t wait for an emergency to happen first!

On the Drs Letterhead,  a brief explanation of CAD is helpful.  Blood Draw instructions necessary,  and IV warming is necessary.  Ideally to 37°C (Especially IV’s of Saline, Plasma, etc).  Dr signed, Dr Credentials, and Dr Contact information.

This pre-warming/warming, does not apply to some IV Pharmaceuticals such as Rituxan though…..just in case that comes up.

This may not affect the group of CADs that have lower reactions to the cold.  But ones that react easily you need to be concerned about cold fluid being introduced into your body via IV.  It can cause clumping of your blood.  Just how severe or what complications that may arise depend on many factors.

Your loved ones/advocates need to know this info. Your medical ID bracelet should state it. Your medical records, should state this. All in case you are unconscious or unable to speak. A serious traffic accident would be a prime example situation. Your advocate might not be around.

Phones such as the iPhone now have an emergency section first responders can access.  Also put this info in notes with a brief explanation of CAD and the precautions to not infuse cold IVs in the case of an emergency.  Perhaps your CAD treating doctor’s name, and contact telephone number?

Make paper copies to present and/or have attached to your chart. Then it is best to arrange a special blood draw appointment.  Where the informed lab manager or supervisor is present, and involved. Or at least agreeable you have to be handled/tested differently and has instructed their staff.

Some of our worst experiences are when admitted to an ER. You are basically trapped and some medical staff personnel are very close minded to a patient that has some rare condition. Guessing you are written off as another complaining unrealistic patient. Sorry, but we have encountered this way too often.

Surgeries are another concern.  Again CAD sensitivity level may dictate special considerations.  But that is material for another entire discussion.

I can’t stress enough that you better have paper copies of your Dr’s blood draw instructions for the ER, and your chart. If you are admitted after hours all of this often turns into a giant conflict…especially if they can’t reach your doctor!

If you are admitted because you know you have low red blood counts (Anemic), and not thinking clearly….. it makes matters worse. You definitely need an advocate that is aware of your condition, have written documentation along, and be somewhat educated on blood result numbers and what they mean.

Stick to your guns when approached by a Tech that you know does not know the “Keep it Warm” process [If you are in that stage].  I must say here that this is no official term any facility uses.  You have to feel the tech out by starting….I have Cold Agglutinin Disease.  Are you prepared to keep  my specimen warm?  Is the lab on board?  Are you getting a blank stare???

Stick to your guns about having Saline IV’s run through warmers too.  Especially concerning is emergency first responders that may  have no training concerning CAD, then attempt to infuse you with cold saline while on the way to the ER.

We generally flag down an “In Charge” nurse before this ever comes up.   It helps avoid a tech walking up to you, then getting blindsided when you start throwing questions.

A good indicator the tech is not on board is they have no means of warming the tubes.  [Again, if you are in the “keep it warm” stage]

As the disease progresses the patient may experience failed or erroneous results, unless the blood is kept warm the entire process.  You will know when that point in time arrives.  That is when your conflicts will most likely begin.

In our experiences some hospitals and labs dealing with CAD patients have become more aware the drawing tubes must be pre-warmed, warmed the entire time the blood is in transit to the lab, and the lab must keep it warm and tested STAT.  But you have to make it clear you are CAD.

Once alerted, some medical facilities are prepared and use “baby heel warmer” wrapped tubes, or beakers of warm water. If they arrive for collection without it and you know you are at the point it is necessary, it is time to say “stop”.

Start the discussion. Not with that tech, but a supervisor, “In Charge, or attending Dr. You will more than likely have to make waves.  Because if they aren’t on board, neither is the lab.

Unfortunately many facilities, Doctors, and staff, are entirely clueless concerning this “warming” technique or the Lab handoff/testing STAT.

We have encountered honest Doctors and Techs will admit they know no special protocol. Never heard of such a thing,  Most have no exposure dealing with a CAD patient.  Some I suspect won’t even believe you if they don’t research it.

We still carry paper documents when a trip to the ER is necessary.

In our case, after some years, things progressed even beyond the “keep it warm” technique. In some patients that even fails to work. They and their Doctor will have to really work with a facility to move into testing using a non-standard testing Protocol.

We have had several facilities refuse to alter their protocol. With test after test failing at their lab, we were finally told to go somewhere else.  Quest, LabCorp, and CPL have all told my wife they could no longer test her blood.  They stated they would not alter their standard protocol to accommodate her once the “Keep it Warm’ process started consistently failing.

That is great if you have insurance that will let you go anywhere else you please. With things the way they are with our insurance we are limited to specific labs. You know…. the lowest bidder it seems.  The ones that won’t work outside the box.  We are not sure what others are encountering with socialized medicine?

Sure we can go other places and pay the bill!  We have PPO insurance and we are getting this. I can only image what HMO, Medicare, or “managed health care” patients might be dealing with?

We had an in house Hospital Lab manager providing a testing procedure they are now using to produce accurate blood test numbers on such a patient. The type of patient that “keep it warm” no longer works.

Unfortunately they will not take Marilyn on an out patient basis.  To do a CBC/RBC through an ER visit (which she has done on occasion) costs thousands of dollars.  We have had to go that route on two occasions.

Her Hematologist used the same information (Plasma Replacement Process) at a second hospital that set up a special outpatient account.  So Marilyn can walk in as an out-patient for a blood test.  Why this is so difficult is way beyond my thinking.

Whether you can convince your Doctor, or your Lab, or some Hospital to follow the process. Will really depend on how open minded they are. We dealt with numerous failed tests for years.  Some ER bills approaching $5000 to basically run a RBC/CBC.

Someone is finally just now listening and taking the time to get involved. Things shouldn’t be this way. But it sometimes takes that special person, or special doctor to perhaps open that door for you.

It would be nice if some professional(s) in the medical community would pick up the torch on all of this. Have the protocols altered nationally (Globally) for CAD patients.  To produce accurate and consistent test results, regardless of their cold reactive-ness.

Many do not understand CADs.  Many CADs often live on the edge of being anemic.  Often even below the average acceptable range of a healthy person.    Common colds can often tip that fragile balance.

That is the trouble with us Lay people that do not have the technical or medical knowledge, or influence, to change any of this. We just see the waste and delay, and have to deal with the frustration.

Send Updates to: See Contact US
Advocate for a Loved one with CAD. For nearly 20 years (as of 2019)

Lately it is rare to find a compassionate medical professional that takes the time to go above and beyond, and gets involved. They are truly the few and far between these days.  They are truly appreciated.  Real hero’s to CADs.
The below document is verbatim from our written document from a Hospital Laboratory Manager. When Marilyn is in this hospital a copy of the below document must be presented at each blood draw.

The wording is not that of a lay person, but a medical professional, a lab supervisor, of major hospital.

We are reluctant to post the name of the person or Facility fearing they may no longer be willing to work with us should people start contacting them.

We do hope this may help others that experience the same Blood Testing failures Marilyn eventually did.


To Print only the below info rather than this entire article click PRINTABLE FORM ONLY

Date 11/19/16
Subject: Strong Cold Agglutinin for
(omitted patient name)

The CBC for (omitted patient name) will require special handling. Tube must be prewarmed using infant heel warmers and tube needs to be kept warm after collection and delivery straight to the lab.

Heme tech: Put CBC tube in 37 degree heat block. Have blood Bank put saline in 37 degree water bath for 1 hour. Perform plasma replacement technique on separate CBC tube with prewarmed saline. Return to CBC tube to 37 degree heat block for 1 hour. Run well mixed tube on hematology analyzer in manual mode, do not allow results to autoverify.

Report results with documentation of steps taken. Report whether hemolysis is observed in the supernatant while processing.

A Copy of these Written Instructions must accompany tube to lab department.

Thank You

(Omitted Lab Manager Name & Facility)