Monday, September 9, 2013

How to Pass the NGSP A1c Proficiency Testing Survey Like a Pro

 Proficiency Testing (PT) of clinical laboratories is an important part of Laboratory Quality Assurance

All clinical laboratories participate in subscription type PT such as (CAP) or CDC Lipid Survey in addition to State Sponsored PT programs such as N.Y. State DOH or PA DOH, etc.  One of the toughest most difficult PT surveys to pass in my opinion is either the CDC Lipid Survey or the
NGSP - National Glycohemoglobin Standardization Program.
HBA1c is a component of Hemoglobin that is glycated (Hemoglobin + Glucose) at normal levels in patients with normal sugar metabolism.  Individuals with diabetes do not metabolize sugars normally and therefore glucose levels in the blood are erratic leading to all sorts of ancillary disease states of the kidneys and circulatory system as well as negatively affecting ones vision and propensity to develop infections.  Good glucose control is the key to surviving with diabetes for an extended lifetime.  Those with poor control of glucose suffer many different ways on a daily basis and do not live a long life time.  As a clinical laboratory it is for the good of all people to be able to produce the most accurate reproducible data possible day after day, patient after patient, normal and abnormal.  Passing a HBA1c CAP survey is good but passing NGSP is better.  Then there are some patients that have a Hemoglobin make up that interferes with all HBA1c testing methods. For more info on that click here;Testing interference with HBA1c

NGSP is a subscription PT testing program that challenges all aspects of a laboratories glycohemoglobin testing including the testing platform, reagents, calibrators, user technique, and ancillary equipment.  NGSP is the ultimate PT QA program for ensuring quality in testing and reproducible results in HBA1c testing.  Click here for more info about obtaining certification. The data analysis of the NGSP PT results are so exact and statistically critical; passing this survey a difficult endeavor to undertake.  I know, I have managed a laboratory that successfully passed the NGSP for 5 years straight while employed at that lab.  Possibly not as excruciating to pass as the CDC Lipid Survey which I also participated in and actually visited the laboratory at the CDC in Atlanta that prepares the specimens for the CDC Lipid Survey.  I sat down to talk with the director in charge of administering the CDC Lipid Survey program; that was really neat.  The next CDC Lipid PT I had overseen passed as well.  Although, continued success with the CDC Lipid PT is almost impossible under the scrutiny of any manager.

Let me tell you about my experience with the NGSP PT Survey and offer some helpful hints to any laboratory wishing to endeavor down the path of NGSP Certification.  NGSP is a certification process whereby a laboratory, instrument vendor, or other entity is awarded certification for one year.  Renewal of the certification occurs on an annual basis on the certified labs anniversary.  There are 4 testing events throughout the year including the certification or re-certification process and 3 quarterly testing events.  Each testing event consists of small samples shipped from NGSP HQ on dry ice to the subscribing laboratory.  Each testing event must be completed within stipulated time period with results emailed, shipped, or otherwise electronically returned to the NGSP program for analysis.
NGSP will statistically analyze submitted laboratories data and compare against other certified laboratories.  The comparison performed may be against same method or different methodology.  It really doesn't matter who is used as comparison.  NGSP is the standard by which all instruments, methods, and laboratories are compared to.  Your lab either compares or does not.  If your lab compares well enough on the certification PT process Level II certification can be obtained.  If your lab performs really well, Level I Certification is obtained.  Currently for 2013, there are 138 laboratories worldwide that are certified with 100 certified as Level I labs.  There is a reason why some lab can only achieve Level II certification - The process is arduous, difficult, stressful, and fraught with possible minute unknown errors in testing that can skew results tenths of a percentage which can make any lab a Level II lab.  It is rather stressful simply because the annual expense  is $5000 USD for a Level I lab and once you achieve Level I and the status the certification brings to a lab it is terrible to lose that status.  NGSP and the directorship of that program are globally recognized as experts in HBA1c metabolism, testing, testing methods, and testing procedures not to mention a fine PT program with astute statistical data analysis.  If your lab is contemplating NGSP Certification then buckle up ~ you are in for a rough ride.  Put up your money and get prepared to take a beating.

Ok lets get started - What do you need to know?
1st - NGSP is not your run of the mill CAP survey.  There are more samples to test than CAP and lets face it passing a CAP survey for HBA1c is like driving a car through the Lincoln Tunnel.
 CAP HBA1c 2013 Summary  The data analysis applied to the NGSP  survey program is exacting and tight.  There is no room for error and minute changes in instrument function form day to day will bring you down to Level II fast.
2nd - Do your homework.  Go to NGSP on the World Wide Web and look around.  See who is listed as Level I and Level II.  Make sure you take note of the manufacturers and what they routinely pass as either Level I or Level II.  If a particular instrument can't routinely make Level I what makes you think you can do better with the same instrument on your lab bench with your scientists? If you don't have a Gold Standard method think about getting a Gold Standard method Such as Tosoh or Bio-Rad before going down this lonely country road to NGSP Certification.
3rd - Make sure you have well trained scientists who can tell the instrument is not running right on a minutes notice and can rectify issues expertly.  Also, make sure your maintenance program is fastidious and complete without lapse.  Make sure your chemistry is spot on.  Everything about your instrument has to be perfect or even Level II will be out of your grasp.
4th- If you currently have QC ranges that you can drive a city bus through (> 0.3% HBA1c on any given level of Quality Control) and use every tenth of that range on a monthly basis you are going to fail miserably.  Don't even think about NGSP if you can't handle an sd of 0.1 across your whole testing linearity.  Your lab will fail miserably otherwise.
5th - Once Level I Certification is obtained a Level II testing event will place your lab on "Probation".  Passing the next quarterly event with Level I is a necessity otherwise your Lab will be officially graded as Level II for your poor Level II two testing event performance.  

So- you have the nerve to force your scientists to a 0.1 sd under much grumbling from them and you are confident for several months like that.  Go ahead - go for it.  Just know that one little slip of the wrist during pipetting, diluting off by tenths of a %, and any maintenance lapses will cause unknown suffrage and possible failure.  Even Level I labs suffer an inconsistent Level II testing event now and then; in five years of straight NGSP testing I had two Level II events; that was 90% Level I for 5 years.  If you consistently use the same instrument, the same scientist, the same pipettes, chances are your consistency will prevail a strong Level I performance time after time.  But, that is not reality.  If you have the stomach like I do you will monitor everything like a crazy nut ensuring that no matter what instrument, what scientist, what pipette, what Lot number of reagent, and what calibrators are used, and dam those torpedo's. I passed year after year after year.  Yeah - that's how you do it.  I had 6 instruments and 7 scientists and rotated amongst them all with expert success.  Am I bragging - You Bet! "Don't try this at home folks I am a professional".

 Alright you take the plunge - You purchase your certification kit and wait for it to arrive.  Now what?
Make sure you have staff on hand that can competently receive and store the testing kit once it arrives at your facility.  You must keep the kit frozen at -80ºC at all times until ready to test.  -20ºC is going to ruin the samples.  If the kit gets lost in your facility and the samples thaw uncontrollably you are going to have to beg NGSP for another kit.  Do it a second time and you may not get a replacement kit.  If the kit gets lost along the way you must let NGSP know immediately after the expected receive date.  That is not the labs fault.  But, once the package is signed for it is yours.

Make sure everyone involved in the testing is trained well, knows what they are doing, can handle the 0.1 sd QC no problem, and did I say they must know what they are doing???  I am not kidding.  There is no room for minute error in the NGSP statistical analysis.

Make sure your instrument maintenance is up to date or complete it before the testing event starts.  Be careful though.  You must also ensure mechanical performance will continue for the testing event.  The last thing you need is for mechanical failure in auto dilution area of the instrument day 3 or 4 into the testing event.  If this is your Certification Process - you better pray nothing happens during the 20 days of testing!  You bet. That is what I said.  Certification is 20 straight days of testing HELL!  If anything breaks down during that time, you better fix it and fix it so the instrument performs just the same as before it broke.  Hence you will fail miserably.

A word about calibration.  Most HBA1c instruments produce a calibration from two analyzed samples in the calibration kit and that kit is compatible with certain or single lots of reagent.  Make sure you are following instrument manufacturer guidelines for use of calibrators exactly as specified.  No cutting corners, no deviations, no mistakes or you will fail NGSP miserably.
You must make sure everything about the testing instrument is perfect, producing the same result on the same sample day after day after day.  NGSP is not only testing for accuracy but just as importantly reproducibility.  Don't kid yourself and don't be a fool. Preparation is the key.  Human error is the enemy, instrument mal-function on a sporadic basis is the unknown.  You will know something bad happened that you were not aware of when you get your results back from NGSP and you missed Level I by 0.03 or something minute like that or worse yet don't even make Level II performance.

Ok, so I think I have successfully scared anyone unknowing of the the NGSP process.  Can it really be that bad?  Yes it can.  Can Level I labs fail now and then? Yes.  Will they ever figure out what happened? Possibly not.  Will they pass next event with Level I performance?  probably yes.  But just remember, out of 139 certified labs only 100 attained Level I Certification.  39 labs were unable to attain Level I performance for two straight testing events!  Here is what you really need to know to successfully pass this arduous PT program.  
  • Xanax will be your friend.
  • Treat your NGSP testing kit samples like gold.  Refreeze them immediately after done testing the samples for the day.  Don't waste them.  Don't wait hours to refreeze either.  Unstable NGSP samples are a terrible thing to use.  Make sure they are clearly identified for future use.  NGSP knows labs save the samples for future reference and they send only about 0.5 mL of sample in each tiny vial. Re-test old NGSP samples before the testing event starts.  This will insure exact analysis is coming from your instrument.  If you have more than one instrument then test against both or two or three of your available instruments.  Pick the best performing instrument.
  • Once you establish that your instrument is analyzing exactly as needed Do Not Make Any Changes that will affect performance.  Get your maintenance procedures done an any instrument that may be used for NGSP, preliminary test with old NGSP samples and calibrators as unknowns, then promptly start NGSP if you are satisfied.  The more time that elapses after you "prelim" the instrument and NGSP testing starts the more unknown can happen.
  • If your staff is not comfortable using such small quantity of PT sample in a small tiny vial then have them practice with such small vials before the testing event begins.
  • Save calibrators that were used during very successful NGSP testing events.  Test these calibrators as unknowns in the same manner as true NGSP samples will be tested in your lab.  Make sure you are recovering exactly the data you expect with the saved calibrators.  This can be used as a reference mark to make sure analytically your instrument is performing optimally before the NGSP testing event commences. 
  • Make sure any pipettors used are in good mechanical order and are calibrated as exact.  This is going to be the most common issue that will bring you down to Level II or fail you miserably.  I cannot stress this enough.
  •  Make sure you have enough reagent on-board to complete the testing event.  If you run out of reagent mid way and change even a buffer solution, you run the risk of failure.
  • Make sure your scientist is a pipetting expert.  Pipette by the book.  There is no room for slouching here.  Practice can be obtained via a laboratory scale.  The testing scientist must be able to pipette minute sample amounts with the same accuracy time after time.  Practice until perfect.  Did I already say that pipetting errors will bring you down?  Take heed.  Make sure the technique is spot on perfect.
  • Make sure you know what type of freezer is used to store the NGSP test kit.  If you store in a frost less freezer you will ruin the samples.  It is a done deal.  Get yourself a good lab grade freezer that will not cycle off and on furiously to avoid frosting.  Yes they are expensive and frost will build up inside like a glacier but that is the only way to successfully store the kit and any samples you save from the kit post test event for future reference.
Overall you must be confident in your technology, your technique, and your abilities.  If you have all three you will pass.  If you falter, well you know the end result.  Level II or worse and ultimate humiliation of not passing a PT you paid good hard earned money for the nerve to take a numb skull crack at it try.  

If NGSP is for you - know well what you are getting into.  Only a short list of labs can pass this strict PT program. Will you be one of them?  Do you have the nerves of steal?  Do you have the knowledge and experience with your testing method to realize what is good and what is bad data and how to fix that mess?  If so, see you in the winners circle!

 Take care my brave friends - Test with confidence and see you in the NGSP winners circle.

Scott R. Mayorga A.A.S., BS MT(ASCP)H CLS


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