Mock OSCE Debriefing

Station No 1 Glucose estimation  Principle  Requirements Semi-automatic analyser Adjustable pipette GOD-PAP reagents Working literature Glucose Standard Two levels of QC material Value sheets of QC

Station No 2 Levy Jennings’s Plot  Calculation of basic statistics  Plotting of Levy Jennings’s (LJ ) charts  Application of Westgard`s Rules

Station No 3 External Quality Assurance  Method means  `Z` value for bias (accuracy)  Allowable bias  Plots for precision (Bio-rad)

Station No 5 Method Evaluation  Any step involved in method evaluation can be asked  Requirements include: Semi-automatic analyser Adjustable pipette GOD-PAP reagents Working literature Glucose Standard  Glucose solution (25%)

Station No 6 First scenarios  A female patient has very angrily complained you about a beta-HCG report from your lab. Your result is 1500 IU/L while she got reports of < 1.0 IU/L from other two labs within 24 h of the first test. You repeated the test with another sample and found that it is < 01.0 IU/L from your lab, too. This gross variation is a matter of concern for you, so after apologising the patient you obtain the raw data of the test from the autoanalyser which shows following results of the batch.

Raw data of autoanalyser Sr NoBeta HCG result 112< , < Most Probable Cause: Sample carry over.

Station No 6 Second scenarios  You have just started an Arterial Blood Gasses (ABG) system which also incorporates electrolyte analysis. During the first day of analyses of patients` sample the result of Sodium worries you, some of them are like following:  Most Probable Cause: Use of Sodium Heparin as an anticoagulant.

Station No 6 Third scenarios  You have received a call from the Intensive Care Unit about Calcium and Electrolyte reports of two patients with gross Hypocalcaemia and Hyperkalaemia which are otherwise apparently normal.  Most Probable Cause: EDTA Contamination

EDTA Contamination  EDTA binds Calcium  False Hypocalcaemia  False Hyperkalaemia “Spurious hyperkalaemia due to kEDTA contamination is common “ Michael P Cornes1, Clare Ford and Rousseau Gama; Spurious hyperkalaemia due to EDTA contamination: common and not always easy to identify Ann Clin Biochem 2008;45: doi: /acb © 2008

Correct Filling Order  Always fill Plain tube and Lithium Heparin tube first  Followed by EDTA tubes (Glucose and CP tubes)

Right Order Serum and Lithium Heparin First CP and Glucose last

Station No 7 Derived Tests Creatinine Clearance  Urinary Creatinine: 8.5 mmol/L  Serum Creatinine : 98 µmol/L  Urinary Volume: 1440 ml  Creatinine Clearance : ml /min

Station No 7 Derived Tests HOMA –IR  Plasma Glucose Fasting: 6.8 mmol/L  Serum Insulin: 18.3 IU/L  HOMA –IR : 5.53

Station No 7 Derived Tests Delta Ratio  pH : 7.57 (7.35 – 7.45)  Base Excess: 7.0 (+3 to -3)  PCO2 : 2.8 (4.7 – 6.0 kPa)  PO2: 19.2 (10.7 – 13.3 kPa)  HCO3: 21 (22 – 28 mmol/L)  Chloride: 80 ( mmol/L)  Anion Gap: 33 (7-17 mmol/L) Delta Ratio: 7

DELTA RATIO The delta ratio is used for the determination of a mixed acid base disorder in an elevated anion gap metabolic acidosis Measured anion gap – Normal anion gap Normal [HCO3-] – Measured [HCO3-] or (anion gap – 12) (24 - [HCO3-])

Station No 9 Data Interpretation a. A patient having following arterial blood gas analyses results:  pH : 7.40 (7.35 – 7.45)  Base Excess: 21.8 ( -3)  PCO2 : 10.7 (4.7 – 6.0 kPa)  PO (10.7 – 13.3 kPa)  HCO (23 – 33 mmol/L)  Oxygen Sat 95.1 (95-98%) What is the most probable biochemical diagnosis: Correct Answer: Mixed Respiratory Acidosis and Metabolic Alkalosis

Station No 9 Data Interpretation b. A 60 year old female presented with polyuria and nocturia: Serum  Ca : 3.21 mmol/L (2.15–2.55)  PO4 : 2.5 mmol/L (0.60 – 1.25)  Albumin : 43 g/L (37-52)  ALP : 114 U/L (30 –120)  Urea : 6.2 mmol/L (3.3 – 6.6) What is the most probable diagnosis? Correct Answer: Vitamin D Intoxication

Station No 9 Data Interpretation c. A boy of 15 years presented with oedema all over the body: Serum  Total Proteins: 55 g/L (65-80)  Albumin: 25 g/L (35-50)  Serum Cholesterol : 8.5 mmol/L (<5.1)  Serum Triglycerides: 1.8 mmol/L (<2.83) What is the most likely diagnosis ? Correct Answer: Nephrotic Syndrome

Station No 9 Data Interpretation d. A 22 year old female complained of hair growth on face and limbs with regular menstrual cycles: Serum  FSH : 6 mIU/L (2-10)  LH : 20 mIU/L (3-14)  Testosterone: 5.8 nmol/L ( ) What is the most probable diagnosis? Correct Answer: PCOS

Station No 9 Data Interpretation e. An infant with ambiguous genitalia and failure to thrive:  Karyotype: XX What is the most probable diagnosis? What investigations you will like to carry out? Correct Answer: CAH 17 OH Progesterone