Radiometer ABL 90 Analyzer Acceptable Samples

Hi Donna,

Here is the info for our Lab SOP. We use serum for ionized calcium on our ABL90:

  Serum from whole blood, collected in SST tube, anaerobically.  Tourniquet must remain on during collection but not longer than 3 minutes. Tube must be filled and not opened until analysis. Centrifuge within 4 hours. Specimen is stable for 70 hours when stored at 4⁰ C.

  Contraindications/Limitations/Sources of variability

• Electrolyte balanced heparin must be used to prevent the binding of Ca++ ions by the heparin, and an excess of heparin must be avoided.


• Exposure to air can cause loss of CO2, and raise the pH. Underfilled tubes will also cause this to happen.


• Do not use liquid heparin as it can dilute the sample and produce reduced results for some parameters, by as much as 10%.


• Hemolyzed samples (greater than 30 mg/dl) cause clinically significant decreases in Ionized Calcium.


• Whole blood specimens must be well mixed prior to sampling. Specimens sitting for up to 30 minutes may have settled completely and a thorough mix is required.

We have ABL90s at our hospital.  We only have used syringes.  Your question prompted me to find the answer in the ABL90 FLEX operators manual.  It clearly shows 3 types of samples - safePICO syringe, capillary tube and test tube.  It doesn't however state what type of test tube.  What does the vendor say?  This is a great question.

Kathy

Thank you for the feedback. So I have talked to our clinical specialists and he said, lithium heparin tubes are acceptable as long as they are don't have serum separator gel. He said the gel from the tubes may cause problem in the long run. He also advised us to use clot catchers because RT's are using the lithium heparin syringes that contain silicon and silicon can also damage the analyzers when it builds up.