Clinical Pathology Laboratory Activity EMS 2012
• Blood Glucose Measurement• Kketone and Glucose Urine Exam
• Blood Gas Analysis• Cholesterol Examination• Cortisol Measurement
Factors influencing laboratory results
Pre analytic
Analytic
Post analytic
Glucose Measurements
SPECIMEN CONSIDERATIONS
Whole blood Plasma Serum Pleural fluid CSF Urine
Most measurements by enzymatic methods:
1. glucose dehydrogenase, 2. glucose oxidase, 3. hexokinase
Glucose Measurements
1. Glucose Dehydrogenase
2. Glucose Oxidase,
3. Hexokinase
(Henry JB. Clinical Diagnosis and Management by Laboratory Methods. 2011)
• These reactions produce an electrical current that is proportional to the initial glucose concentration, or a product that measured spectrophotometrically is proportional to the initial glucose concentration.
• The assays can be initial rate-of-change assays, where the velocity of the reaction is dependent on the initial glucose, or end-point assays.
Glucose Measurements
Spectrophotometer
POCT (point of care testing)/ Blood Glucose Home Monitoring/ Self Glucose Home Monitoring
Glucosemeter
Spectrophotometer
POCT (point of care testing)/ Blood Glucose Home Monitoring/
Self Glucose Home Monitoring
Method of POCT (point of care testing)/ Blood Glucose Home Monitoring/
Self Glucose Home Monitoring
Biosensor
Reflektansmeter
Biosensor Method
Biosensor Method
Reflektansmeter/ Amperometer Method
A wide variety of devices are available forhome measurements:
• avoiding operator errors• Calibration• Errors that may contribute to inaccurate readings in certain
devices include the application of :- an insufficient volume of blood- milking the finger to acquire sufficient blood- the use of outdated test strip- environmental factors (humidity, heat, altitude)- the use of a malfunctioning meter- the use of a dirty meter - hypertriglyceridemia- hypotension- measurements outside of the hematocrit or temperature range
Influecing Factors
• Influenced by high levels of salicylate, acetaminophen, levodopa, uric acid, bilirubin,lipids, or low oxygen levels, and others are altered by touching the reaction area.
• Vit C, lactose, manose, galactose, xylose .
Reference Value
Ketone and Glucose Urine Exam
Dipstick Urine Test/ Strip
Urine test strip:Rapid, easy, specific,cheap
SPECIFIC GRAVITY
PROTEIN
KETOBODY
UROBILINOGEN
BLOOD
PLASTIK ROD
NYLON COVER
NITRITE
GLUCOSE
TEST FIELD(PAPER CONTAIN REAGENT)
FILTER PAPER
DIPSTICK TEST
Dipstick urine test
1. Specific gravity2. pH3. Leukocytes4. Nitrates5. Protein6. Glucose7. Ketones8. Urobilinogen9. Bilirubin10. Blood
Glucose (negative)
Glucose is normally present in glomerular filtrate, but it is reabsorbed by the proximal tubule.
D-Glucose + O2 δ-D gluconolactone + H2O2
GOD
H2O2 + 0-tolidine H2O + colourPOD
Ketones (negative)
in healthy individuals, ketone bodies are formed in the liver and are completely metabolized so that only negligible amounts appear in the urine
sodium nitroprusside and glycerin + acetoacetate and acetone
alkaline medium violet dye complex.
URINALYSIS STEPS
PRE-ANALYTIC : patient preparation, samples collection, samples handling, labelling, refrigeration, preservatives of urine specimens.
ANALYTIC: principle of procedures, measurements, interpretation, conventional & rapid and sophisticated
POST-ANALYTIC: recording, reporting, use of units : conventional unit and international unit
QUALITY CONTROL (QC):calibration, control solution to get good and reliable results
Pre-Analytic1. Specimen collection- Requisition form must accompany with specimen
delivered to the lab; the form include : patient’s name, I.D number, date and time of collection and additional information : age, location, physician’s name, type of specimen/method, interfering medication and clinical information
- Container clean, dry, leak proof, disposable - All specimens must be properly labeled must be attach
to the container, not to the lid, should not become detached if the container is refrigerated
- The information on form requisition match with the inform on the label
Labelling urine specimen
Name (min 2 initial, ex: Deni Darmawaty)
Sex : female
Date (day, month, year)
Time collection:
Adress and telp number :
Pre-AnalyticTwo Type of Specimen Based on Time :
- Random specimen- First morning/fasting specimen- 2-hours post prandial specimen- Timed urine (12-hours, 24-hours specimen)
Based on method :- Midstream Clean-Catch specimen- Catheterized specimen- Suprapubic aspiration
Type of Urine Specimens Purpose
Random Routine screening
First morning Routine screeningPregnancy testsOrthostatic protein
Fasting (second morning) Diabetic screening/monitoring
2-h postprandial Diabetic monitoring
Glucose tolerance test Accompaniment to blood samples in glucose tolerance test
24-h (or timed) Quantitative chemical tests
Catheterized Bacterial culture
Midstream Clean-catch Routine screeningBacterial culture
Suprapubic aspiration Bladder urine for bacterial cultureCytology
• The first morning urine:
Collected upon rising, it represents the urine over
approximately an 8 hour period
• Ad random urine:
Collected any time
• The 2-hour postprandial urine:
Collected 2 hour following the meal ( for urine glucose)
• The 24-hour urine:
A pooling of all urine excreted by the patient over a 24 hour period
(for protein, uric acid, calsium quantitation, etc)
• Midstream urine:
The middle portion of a single urination
Pre-Analytic
3. Specimen HandlingFolowing collection should be delivered to the lab promptly and tested within 1-2 hoursIf it can’t delivered must be refrigerated or add with chemical preservative
LIMITATION OF THE METHOD AND INTERFERING FACTORS:
• Highly pigmented or large amounts of levodopa metabolites in urine may cause weak positive result
• High Specific Gravity and low pH urine and PSP (phenolsulfophthalein) may cause false positive result
• High-protein, carbohydrate-free, high-fat diets may result in ketonuria (false posi- tive)
• Medications : phenazopyridine , ascorbic acid, ether, insulin, isopropyl alcohol, metformin, isoniazide, isopropanol, paraldehyde, valproic acid, and bromsulfoph- thalein also can cause false positive results
EXPECTED VALUE
• In starvation diets or in other instances of abnormal carbohydrate metabolism, ketone appear in urine in excessively large amounts before serum ketone are elevated.
• This test detected 5 mg/dL of aceto-acetic acid; 70 mg/dL acetone; but more specific for aceto-acetic acid.
Lipoprotein structure