gel diluent qc

[Karen knight 3]

Hello, we are currently validating GEL, how are you QCing diluents? instructions for use says it should be done daily w known pos and neg, along w visual. we are using confidence kit.  in order to use diluent 2 plus for daily qc, do you pipette 200 ul of 3% cell 1 in test tube, centrifuge one min to pack cells, remove supernatant, pipette 150 ul of MTS diluent 2 plus, mix to resuspend, procede on with QC. if an eagle-eyed CAP inspector asked how we QC diluents, I want to be ready. there is mixed opinions in lab, some think we can use 3% cell 1 as is? but then diluents not used for qc?

Also, once opened, what is exp date for diluents? thanks!

 

 

[SMILLER 831]

We use diluent to make up the negative and positive control solutions for checking the screening cells.  That seems adequate.

Scott

[Karen knight 3]

ok, thanks!  as we are figuring out our gel validation, we were actually using confidance cell one and 2 as is at first, no dilution. our ortho rep who did our training didnt go over qc at all didn't tell us diluents need to be qc'd.  how about diluent exp date once opened? I couldn't find that info anywhere? we keep in fridge after use

[SMILLER 831]

You would want to check the Ortho Instructions For Use (all Ortho IFUs are online) for stuff like this.  I believe the MTS diluent is listed as being usable until its label expiration date (opened or not).  The notes about QC are there also.

I am pretty sure our Ortho customer rep went over all this stuff with us when we switched from tube to gel years ago.

Scott

[noelrbrown 27]

there is also an FDA cleared product that can be used without any modification or off-label use its called MQC-cat from a company i might know....

[TreeMoss 65]

Check the package insert for the Diluent.  We look at the diluent for clarity and expiration date and make note of that on our daily QC sheet.

[pinktoptube 44]

We make a 0.8% suspension of donor Rhpos red blood cell unit with the diluent and then test it with manufactured control antiserum (as positive control) and saline (as negative control).

[Malcolm Needs ★ 4,439]

21 minutes ago, pinktoptube said:

We make a 0.8% suspension of donor Rhpos red blood cell unit with the diluent and then test it with manufactured control antiserum (as positive control) and saline (as negative control).

I'm sorry, but unless you use the diluent in which the manufactured control antibody is diluted, you are not using a proper negative control.

[SMILLER 831]

On 9/2/2019 at 9:30 AM, Malcolm Needs said:

I'm sorry, but unless you use the diluent in which the manufactured control antibody is diluted, you are not using a proper negative control.

Except that the QC manufacturer's diluent used to make a control antibody solutions is not used in any phase of patient testing--it does not need the be QC'd--it is QC.

I would think the point is that the gel diluent is being controlled (which it should be), by showing it does not produce a positive reaction as a negative control. 

When patient or unit cells are being tested in gel, you use that gel diluent to create an 0.8% suspension--so for a positive gel control, if you are creating your own 0.8% suspension, again you want to use the manufacturer's diluent.

Scott

[Malcolm Needs ★ 4,439]

1 hour ago, SMILLER said:

Except that the QC manufacturer's diluent used to make a control antibody solutions is not used in any phase of patient testing--it does not need the be QC'd--it is QC.

I would think the point is that the gel diluent is being controlled (which it should be), by showing it does not produce a positive reaction as a negative control. 

When patient or unit cells are being tested in gel, you use that gel diluent to create an 0.8% suspension--so for a positive gel control, if you are creating your own 0.8% suspension, again you want to use the manufacturer's diluent.

Scott

That is EXACTLY what I meant.  If saline is used, it is controlling nothing (except, perhaps, that the cells used are not spontaneously agglutinating in saline).

[SMILLER 831]

You almost got it. But I think the original question here was about using gel diluent with QC materials to create positive and negative control cells. 

Scott

[Dansket 425]

On 8/22/2019 at 8:03 AM, SMILLER said:

We use diluent to make up the negative and positive control solutions for checking the screening cells.  That seems adequate.

Scott

On ProVue, there a two diluents, MTS Dil 1 and MTS Dil 2.  These are controlled by running a positive and negative antibody screen test and a positive and negative Anti-IgG DAT test.

[cthherbal 51]

Unless I am missing something, the MTS Dil 2 is not used in antibody screening, however it is used for making a suspension when performing a DAT IgG test (pos and neg QC) on the analyzer. MTS Dil 2+ is used to make the ABORh forward typing solution, which is also QC'd on the analyzer. For the DAT we make our own but for the ABORh and antibody screen QC, we use AlbaQ commercially made QC material (we test O pos, A neg and B pos QC samples) as well as the antibody screens- two vials test pos (anti-D, c) and one vial tests neg.

[Dansket 425]

On 9/6/2019 at 12:59 PM, Dansket said:

On ProVue, there a two diluents, MTS Dil 1 and MTS Dil 2.  These are controlled by running a positive and negative antibody screen test and a positive and negative Anti-IgG DAT test.

I meant MTS Dil 2 and MTS Dil 2+.