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A customer reported incorrectly reported patient results for hba1c on the hlc-723 g8 analyzer.The customer reported out a patient result of 13.2%.The physician stated that the customer does not have high glucose and the past a1c value was much lower and normal.The sample was rerun and a result of 5.4% was received, which was normal based on patient history.The customer performed a precision test involving ten(10) runs of one patient.Nine(9) out of the ten runs were between 7.9% - 8.0% and one was 13.7%.The precision was repeated with another sample and the same pattern was noticed.The customer stated that this issue started after periodic maintenance (pm) was performed.The customer also noticed that the one high sample in the precision would have the highest total area 2100, while the rest were around 1200.The retention time for all samples was 0.58 minutes.There was no indication of any patient intervention or adverse health consequences due to the reported event.
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A field service engineer (fse) followed up with the customer over the phone and confirmed the issue.The fse asked if the one different result contained a p00 peak and the customer stated that it did.The fse explained that results containing a p00 peak need to be scrutinized and may need to be rerun.The fse instructed the customer to adjust the a1c retention time to 0.59 minutes and rerun the sample.The customer stated that the analyzer was functioning properly.No further action required by the fse.The g8 analyzer is functioning as expected.A 13-month complaint history review and service history review through aware date of event for similar complaints was performed for serial number (b)(6).There were no similar complaints found during the searched period.The g8 variant analysis operator's manual under chapter 1 states the following: limitations of the procedure total area dilution studies demonstrate that the assay is linear from a total area of 500 to 4000.However, the optimum total area is 700 to 3000.Abnormal red cell survival the life span of red blood cells is shortened in patients with hemolytic anemias, and the actual life span depends upon the severity of the anemia.As a consequence, specimens from such patients may exhibit decreased glycohemoglobin levels compared to patients with normal red cell life span.The life span of red blood cells is lengthened in polycythemia or post-splenectomy patients.Specimens from such patients may exhibit increased glycohemoglobin levels.Hemoglobinopathies the most commonly observed hemoglobin variants are hbs, hbc, hbd and hbe.These variants in their heterozygous state elute after the hba0 peak in their designated windows: hbs (h-v1 peak), hbd (h-v0 peak) and hbc (h-v2 peak).The hbe (p-hv3 peak) appears between sa1c and hba0 peaks.In all these cases, the sa1c% is reportable when these hemoglobin variants are present in the heterozygous state.When either of these hemoglobin variants is identified, the sa1c% is calculated in a proprietary way, depending on the type of hemoglobin variant, based on the area of sa1c, the area of identified hemoglobin variant and other peaks.When a p-hv3 peak is detected, a flag 43 is also reported.Glycemic monitoring for any patients displaying any homozygous hemoglobin (other than hbaa) such as hbss, hbcc or the double heterozygous sc, cannot be performed using sa1c because there is no hemoglobin a present.Alternative testing is mandatory for these types of patients.Interpretation of results the sa1c measuring range is 4.0 ¿ 16.9%.The ideal retention time for sa1c is 0.59 minutes.The ideal retention time for a0 is 0.90 minutes.Results will not be reported if the total area (ta) is <500 which can be seen in severe anemia.Results will not be reported if the ta is >4000 which can be seen in polycythemia.(see ¿abnormal red cell survival in previous section).The optimal goal for total area is between 700-3000.However, a ta in the range of 500-4000 is acceptable and reportable for whole blood specimens.The chromatogram must be examined for any unidentifiable peaks (i.E., p00, p01,) before the a0 peak.Do not report the result if these peaks exist.When there is a question concerning the chromatography, repeat the sample.If the repeated sample also displays unusual characteristics, it is appropriate to evaluate whether the unusual result is due to an abnormal sample, a procedural error, an instrument malfunction or a sample-handling problem.For further information, see the troubleshooting section in this operator¿s manual.The most probable cause of the reported issue was traced to the user failing to examine the sample and rerun it prior to releasing results to the patient physician.
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