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Pink vs. Purple


hvtimkang

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Our lab recently switched to gel technology (Ortho MTS) and we are using the EDTA (purple top) to perform ABO typing, DAT, Antibody Screening and Crossmatching.

Another colleague questioned this saying that the Pink top should be used instead.

I couldn't find any articles that would help clarify this issue...

Any help?

Thanks

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We can purchase both pink and purple in the same size (7 ml.) We routinely use the pink tubes in Blood Bank just so it's easier for the phlebotomists to send separate the tubes when they are delivering them to the various departments in the Lab.

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I recommend you opt for the Pink tops:

1) They have a 'dry' EDTA (sprayed along the inside of the tube) rather than a liquid EDTA. Hemo machines calculate for this dilution factor, Blood Banks cannot. (I'm surprised this isn't obvious ... to use an undiluted samples.)

2) They are a different color than Hematology samples so they are easily sorted (if you are doing that manually, etc.)

I believe the vendor (we use BD) can provide you with some literature if you feel you need it (seems pretty self-explainatory to me based on the 'dry' vs 'wet' EDTA).

Note: To decrease the possibility of 'artifact' in MTS, invert the tubes (not gently but not vigorously) a few times just before you put them into the centrifuge. Not sure why, but it works!

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I recommend you opt for the Pink tops:

1) They have a 'dry' EDTA (sprayed along the inside of the tube) rather than a liquid EDTA. Hemo machines calculate for this dilution factor, Blood Banks cannot. (I'm surprised this isn't obvious ... to use an undiluted samples.)

2) They are a different color than Hematology samples so they are easily sorted (if you are doing that manually, etc.)

I believe the vendor (we use BD) can provide you with some literature if you feel you need it (seems pretty self-explainatory to me based on the 'dry' vs 'wet' EDTA).

Note: To decrease the possibility of 'artifact' in MTS, invert the tubes (not gently but not vigorously) a few times just before you put them into the centrifuge. Not sure why, but it works!

I agree with the above.........

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I disagree, what's wrong with using the purple tube?

The dilution factor of the liquid EDTA is not going to affect any blood bank testing.

It simple enough for phlebotomists to draw 2 purple top tubes if hematology and blood bank testing are both ordered and, if your lab requires the same level of patient identification and sample labeling as the blood bank does you can use the hematology sample in a pinch.

If you can show me data that indicates a difference in test results between the 2 tubes then some one should tell the FDA so they can force us to stop using the purple tubes. I'm fairly confident that no such data exists.

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I agree with John. As far as Blood Bank is concerned, they are the same (the purple tops we use here have the exact same dry EDTA as the pinks). The only reason we use pink for the Blood Bank is to distinguish it from Hematology, and so that we get our own tube (we're not good at sharing). People have argued that only the pink one has been FDA approved for Blood Bank but I disagree since BD has shown us that it is the same exact tube, except for the color of the cap.

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I disagree, what's wrong with using the purple tube?

The dilution factor of the liquid EDTA is not going to affect any blood bank testing.

It simple enough for phlebotomists to draw 2 purple top tubes if hematology and blood bank testing are both ordered and, if your lab requires the same level of patient identification and sample labeling as the blood bank does you can use the hematology sample in a pinch.

If you can show me data that indicates a difference in test results between the 2 tubes then some one should tell the FDA so they can force us to stop using the purple tubes. I'm fairly confident that no such data exists.

Thanks for that John, I was getting worried.

I dont see how dilution matters at the BB. And yes about the heme sample being interchageable especially when we need a 2nd sample for a first-time patient.

If it isnt broken dont fix it.

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We use pink just to differentiate that the specimen needs to come to the BB and not Hem. Other samples in our lab are labeled with bar coded labels, our pink top BB tubes are 7 mL and they are hand labeled.

The EDTA is the same in pink and purple and I agree with John, the liquid in the EDTA tubes will not make a difference in BB testing.

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From BD's website...

"What are the differences between the lavender stopper BD Vacutainer® K2EDTA Tube and the pink stopper BD Vacutainer® K2EDTA Tube?

The differences are the types of closures and the labeling. The lavender stopper can either be rubber or a Hemogardâ„¢ closure on a plastic tube. Product 367899, a 6 mL plastic tube, and product 367842, a 2 mL plastic tube, both have a distinct pink BD Hemogardâ„¢ closure and product 368589 has a conventional rubber pink stopper. The pink stoppered tubes have blood bank labels and are generally sent to the blood bank laboratory in the hospital. The additive is the same in both tubes."

If my memory serves me correctly there was a time when only the pink top tube was FDA cleared for routine immunohematology testing, which didn't make a whole lot of sense (to me) since it is identical to the purple except for the label and the cap color.

This is from the FDA website on the topic of "approved products" from BD...

"BD Vacutainer Plus Serum and BD Vacutainer Plus K2EDTA Tubes may be used for routine immunohematology testing and blood donor screening. The performance characteristics of these tubes have not been established for immunohematology testing in general; therefore, users must validate the use of these tubes for their specific assay-instrument/reagent system combinations and specimen storage conditions."

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  • 2 months later...
  • 4 months later...

If I recall both tube have EDTA, but at different strengths. Also, the pink tube is FDA approved for blood bank use and the purple is not, but has been used for years without incident. We have gone as far as correlating Hbg levels with both tubes and they matched almost exactly. We did this because we do hemoglobin levels on all positive cord bloods with direct coombs positive results.

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We have been using Ortho gel technology for quite a number of years. When we switched to the gel we started using the pink top tubes. However, the pink top tubes are also EDTA tubes with the same formulation as a purple top tube. So in reality, you can use either the pink top tubes or a purple top tube. Our preference is the pink top tube specifically because we can get more volume-7 ml. as opposed to only 5 ml. or 2.5 ml. (short draw purple). Our only complaint about the pink top tubes that sometimes when stored in the refrigerator the plasma seems to build up some kind of precipitate that in some cases interferes with reading reactions. For that reason, if we need to pull a sample out of the refrig. for a subsequent crossmatch or other testing we will leave the sample sit at room temp. for a while (if possible) or put it in the heating block for a few minutes or centrifuge the sample. We have never been able to get any explanation for this little idiosyncracy of the pink top tubes.....................

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I am wondering what your reasoning is for performing a HGB on cords with positive direct coombs as I have never heard of this being done. I would hate to run those cords through our hematology instrument as so many of them have clots......

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This is a thing I learned years ago from a Neonatologist. He states that cord hgb of less than 12 is low for an infant and something is amiss. A positive DAT can be the culprit as it may indicate an HDN in progress. I had this bear out once with an infant born with HDN caused by Anti-Kell. The cord hgb was 4.5 and the DAT was 3+. the infant required 3 exchange transfusions, but did survive. Yes, the sample can be an issue. We do reject several due to clots and just poor quality samples, but if we find one with a hgb of <12 there is most often some process going on. I guess it is just on of those things one picks up after 41 years as a tech!

Regards,

John

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We use the Pink tops here, mainly because we only want to collect 1 tube for the BB instead of 2 purples. We have a lot of oncology patients and the fewer tubes that we draw the better, plus I prefer the dry EDTA to the liquid.

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This is a thing I learned years ago from a Neonatologist. He states that cord hgb of less than 12 is low for an infant and something is amiss. A positive DAT can be the culprit as it may indicate an HDN in progress. I had this bear out once with an infant born with HDN caused by Anti-Kell. The cord hgb was 4.5 and the DAT was 3+. the infant required 3 exchange transfusions, but did survive. Yes, the sample can be an issue. We do reject several due to clots and just poor quality samples, but if we find one with a hgb of <12 there is most often some process going on. I guess it is just on of those things one picks up after 41 years as a tech!

Regards,

John

Excuse my ignorance, but I thought that tubes from which you have taken part of the sample are not good sources for hemoglobin measurements because you may not have removed the constituents evenly. I know our Hematology department refuses samples that have been spun regardless of whether or not we have removed anything.

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We collected a pink and lavender tube with each cord blood. We mixed the samples, checked for clots and sample quality, then removed enough sample from the pink tube for blood bank testing. Sine the samples were well mixed we felt we were taking constituents out of the tube evenly. We then correlated the hgb on both the pink and lavender tube for 100 samples. We had a 95%+ correlation. We do have samples that are rejected, but overall the procedure is working. We have since changed to collecting a pink and sodium heparin as we have several requests for chromosome studies and Quest accepts cord blod for testing. This saves the infants a needless venipuncture. the odd part of this whole story is that this was our QA/QI techs idea! Yes, it does have some flaws, but overall it has shown to be effective.

John

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We have changed from serum to plasma, using manual tubes, for anticipation of automation with Tango. We seem to have improved our issue with specimens that don't clot and replaced it with a lot of rouleaux. We also are using pink tubes and did see a few specimens when we were validating but now it seems like we see several a day. Is this just a given when using manual tubes and an issue we would not see if we were using manual gel?:cries:

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We went live with our Tango system on May 2, 2011. We use the pink tubes and have not had any sample issues after going live or during validations. I don't have an answer, but we are using Tango with pink tubes and again, have had no sample issues.

John

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