1. IQC, EQC and PT Nantaya Chanarat Department of Clinical Chemistry Faculty of Associated Medical Sciences Chiang Mai university < [email_address] > [email_address]
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3. Types of Mistakes Reported in Thailand BMC Clin Pathol 2001; 1: 5 6 months monitoring, 935,896 specimens - 941902 analyses Pre-analytical mistakes = 1048 ( 0.11 %) = Wrong identification : Physician’s order mistakes, Inapp. Container used, Inapp. Quantity of specimen, Inapp. Quality of specimens
4. Types of Mistakes Reported Internationally Lapworth, Ann Clin Biochem 1994, 31: 78-84 Clin Chem / 1 yr / ~997000 tests / 249000 pts No. of errors 120 => Frequency 0.05% of pts. Pre-analytical mistakes = 31.6% Analytical = 31.6% Post analytical = 30.8% Multiple phases = 6% Identification errors 31%
5. Goldschmidt & Lent, Klin Biochem Metab 1995; 3: 131-40 Whole lab / 6 yr / No. of errors 133 Pre-analytical mistakes = 53% Analytical = 23% Post analytical = 24% Identification errors 58% Impact on patient’s outcomes : None 43% Mild 23% (delay) Moderate 26% (potential damage) Severe 8% (errorneous med .Intervention) Very severe None
6. Plebani & Carraro, Clin Chem 1997; 43: 1348-51 Stat lab / 3 mo / No. of total / errors 40490/189 Frequency = 0.47% of test results Pre-analytical mistakes = 68.2% Analytical = 13.3% Post analytical = 18.5% Identification errors 2.6% Impact on patient’s outcomes : None 74% Mild 19.6% (further investigation) Moderate 6.4% (inapprop. Therapy modif.)
7. Runner et al, Arch PatholLab Med 1993; 117: 573-7 Transfusion labs / 4 wk / 712 hospitals No. of occasions 2 463 727 errors 67 289 Frequency = 2.7% Types & Cause of errors Absent wristband 49.5% Multiple wristband 18.3% Incomplete data 17.5% Partly errorneous data 0.6% Illegible data 5.7% Wrong wristband 0.5%
8. McClelland & Phillips, BMJ 1994; 308: 1205-6 UK Transfusion / 2 yr / 245 hospitals/ No. of errors 111 Death 6 (1/550000 Tx) Morbidity 12 (1/275000 Tx) No adverse effect 93 (1/36000 Tx) Types & Causes : Wrong blood tubes 23 Lab errors 6 Tx wrong blood 82 Results on Patient outcomes
9. Hofgartner & Tait, Am J Clin Pathol 1999; 112: 14-21 2 Molecular (Survey)labs / 10 yr / No. of tests 4234 errors 16 Frequency = 0.38% Pre-analytical mistakes = 44% Analytical = 31% Post analytical = 12.5% Multiple phase = 12.5 Impact on patient’s outcomes : Mild 25% Moderate 50 % Severe 25%
10. Hofgartner & Tait, Am J Clin Pathol 1999; 112: 14-21 2 Molecular labs / 1 yr / (Questionaire) No. of tests 88394 errors 293 Frequency = 0.33 % Pre-analytical mistakes = 60 % Analytical = 19 % Post analytical = 15 % Multiple phase = 6 % Impact on patient’s outcomes : Mild 20 % Moderate 10.2 % Severe 6.4 %
11. Pre-analytical errors/ yr 2000 / San Raffaele Hosp. Types of errors Inpatients Outpatients Hemolysed serum 8494 256 Insufficient sample 3256 102 Incorrect sample 1824 289 Clotted sample 792 80 Incorrect ident 287 2 Lack of signature (Bl Gr) 266 Empty tubes 238 8 Sample not on ice 75 6 Lack/wrong compilation of accom. Tube 120 Tube broken in the centrifuge 57 36 Urine not acidified 24 Open container 20 13 Module withour signature 14 Urine volume not indicated 5 TOTAL 15 503 792
19. Steps of IQC Process @ Optimum condition variance (OCV) @ Routine condition variance - Known value (RCV-K) @ Routine condition variance - Unknown value (RCV-U) @ Statistical use of patients’ results @ Other applications : CUSUM plot, Youden plot, Westgard multirule, Mean-range chart, etc.
27. More Considerations @ Critical Value @ Delta (Prior value) check @ Cumulative Report @ Clinical correlation @ Lab. Data correlation
28. Limitation in IQC @ Control material ไม่เหมือนตัวอย่างผู้ป่วย @ Random error @ การกำหนดค่า True value ที่ถูกต้อง @ Bias @ ไม่สามารถควบคุมขั้นตอนก่อนการวิเคราะห์ @ วิธีการทางสถิติ ถือเป็น Normal distribution @ สิ้นเปลืองทั้งเวลา แรงงานและค่าใช้จ่าย
37. MEAN - RANGE (X-R) GRAPH DATE 2/5/95 2/5/95 3/5/95 4/5/95 5/5/95 5/5/95 6/5/95 7/5/95 7/5/95 TIME 0900 1300 0900 0900 0900 0300 0900 0900 1300 X 95, 96 95,97 97,95 95,93 96,96 92,99 97,99 97,97 99,94 96,95 94,96 99,94 95,96 95,94 93,98 96,98 96,92 93,96 Total 382 382 385 379 381 382 390 382 382 Mean 95.5 95.5 96.25 94.75 95.25 95.5 97.5 95.5 95.5 Range 1 3 5 3 2 7 2 5 6 Note
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40. Case 1 Date Protein Albumin Bilirubin ALP ALT 1/10 6.7 3.1 32.8 127 956 3/10 5.4 # R 20.6 # R 0.6 # R 55 # R 26 # R 4/10 7.2 3.3 39.5 147 1421 6/10 7.1 3.4 35.7 164 1500 8/10 6.8 3.4 31.8 163 1527 # = Delta check failure R = Repeat
41. Case 2 CBC : WBC 30,000 /cu.mm. Platelet 1,300,000 /cu.mm. Serum Plasma Na 138 139 mmol/L K 6.4 4.6 mmol/L Cl 95 98 mmol/L HCO 3 27 25 mmol/L Urea 8.0 8.5 mmol/L Creatinine 0.09 0.09 mmol/L Previous K 5 determinations were 5.2-6.4 mmol/L with unknown cause
42. Case 3 Lab. Results of a man with diabetic ketoacidosis Na 132 mmol/L(132-144) K 6.5 mmol/L(3.2-4.8) Cl 89 mmol/L(98-108) HCO 3 6 mmol/L(22-32) Urea 14.5 mmol/L(3.0-8.0) Glucose 64 mmol/L(3.5-5.5) Blood pH 7.02 (7.35-7.45) AG 30.5 (7-17)
43. Anion Gap (AG) Total anion = Total cation Measured anion + Unmeasured anion = Measured cation + Unmeasured cation AG = Unmeasured anion – Unmeasured cation Unmeasured anion - Unmeasured cation = Measured cation - Measured anion AG = Na + + K + - (Cl - + HCO - 3 ) Ref. Value = 7-17 mmol/L OR AG = Na + - (Cl - + HCO - 3 ) Ref. Value = 2-12 mmol/L
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45. 7. No regulations, reward/punishment Focus only on performance/ test system 8. Focus only on performance/tests system not on total system 9. Data not shown in graph 10. EQA – prolonged response, no discussion or suggestion, low frequency, discontinuous of the program 11. Clinician understandings ? 12. Equivalent QC, Electronic QC, Eq (Big error Less quality) 13. Etc.
54. วิธีการคำนวณเพื่อลากเส้น VIS = 100 ถ้าจะให้ได้ VI ( ซึ่งก็คือ VIS ) = 100 จะต้องให้ % VARIATION ( V ) = CCV พอดี VI = x 100 ตัวอย่าง CCV ของ SODIUM = 1.6% ก็คือค่า SODIUM 100 m mol / l ถ้าวิเคราะห์แล้วค่าที่ได้เบี่ยงเบนไปจากค่าที่ กำหนด + 1.6 m mol / l หา VIS แล้วจะได้ = 100 X = 100 , X = 101.6 V = X - X x 100 = 101.6 - 100 x 100 = 1.6 X 100 VI = V x 100 = 1.6 x 100 = 100 VIS = 100 CCV 1.6 V CCV 30
67. Z = + 2 แสดงว่าผลการทดสอบนั้นยอมรับได้ ( Satatisfactory) Z = < + 3 แสดงว่าผลการทดลองนั้นน่าสงสัย ( Questionable) Z = > + 3 แสดงว่าผลการทดลองนั้นยอมรับไม่ได้ ( Unsatatisfactory)
68. Proficiency test results are reported as standard deviation indexes ( SDIs ). SDI is calculated by the following formula : SDI = (Result – Mean)/ sd
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70. Quality is a Journey, not a Destination Q O L O I O GO