Week 5 Flashcards

Question

how to avoid electrode fatigue

Answer 1

maintenance

Answer 2

-when electrolytes are excluded from the part of total plasma volume occupied by solids like lipids -electrolytes are not distributed throughout the plasma and are trapped in the water phase -when we do results they are usually whole plasma volume when you have indirect measuring -you measure an aliquot that has been prediluted by the analyzer which increases the exclusion effect -results falsely decreased so your fatty absorbs the electrolytes making the result low then you do indirect methods and the diluting makes the result even lower. in normal states its ignored because we assume that water fraction is constant but in disease if your water goes down the solids increase - lipemia measuring directly is not an issue because you measure without a dilution as they occur in your body

Answer 3

-establish a electrode slope that you can use to calculate pt results -standards need to have similar composition as pt samples -the electrode can act different between liquid calibrator vs whole blood - MATRIX EFFECT Change in millivolts is proportional to concentration

Answer 4

-small sample -analyze whole blood without centrifugation -short TAT -very selective and sensitive - picomoles -can measure many at a time -precise -easy to work -can self calibrate -automatic flow cell cleaning

Answer 5

-has 4 layers -measures the concentration or anaylte activity ly light reflectance -light intensity is proportional (not directly) to color formation End point: color, reflectance density = concentration and reflectance is measured at end of reading Two point rate: two reflectance reading done and rate of change is related to concentration Rate: many readings taken as reaction occurs -rate of color change in slide related to enzyme activity

Answer 6

-pt sample put on slide and then it goes through to under layers B-D-glucose + O2 + H20 D-gluconic acid +H2o2 Oxidation of glucose is catalyzed by glucose oxidase to form hydrogen peroxide and gluconate -peroxidase catalyzes oxidative coupling and produces a dye whos intensity is measured by light 2H2O2 + “dye precursors” red dye

Answer 7

-used for electrolyte determination by measuring potential difference between sample and reference electrode -paper bridge with two hole, two ISE and electrical contact areas -when the specimen and ESF are put into the two holes they move toward each other and form a stable junction -measure the difference between the two half cells which is the conversion to analyte concentration

Answer 8

-multilayered slide with two ISE each with methyl monensin (ionophore for Na), reference layer and Ag/AgCl coated on a polyester support -put one drop of pt sample and one of reference fluid and both migrate to center of bridge forming a liquid junction connecting reference and sample electrode -there is a electrochemical response to Na creating a potential difference between the two electrodes

Answer 9

-consists of ion selective membrane - Valinomycin with a KCl reference layer, Ag/AgCl layer

Answer 10

Sodium -regulated by kidneys -low levels caused by increased excretion, diarrhea, Addisons (not enough Cort or ALD) and renal disease -high due to dehydration, brain injury, diabetic come, K -electrolyte imbalance, cardiac arrhythmais, muscle weakness, renal failure -must monitor in ketoacidosis in diabetes -low levels occur in vomiting, diarrhea, alcoholism, folic acid deficiency -high K due to renal failure, hemolysis, trauma, Addisons acute starvation

Answer 11

-POCT -blood gas, lytes, metabolites, Hb total and derivatives -ABG, VBG, CBPG

Answer 12

-potentiometry, amperometry and conductance to measure sample concentration -signal porpotional to concentration -highly selective scanners -uses thickfilm technology and solidstate design -need small volume -needs no maintenance , no replacing fill solutions just replace the cartridge

Answer 13

pH- Expresses H+ activity; H+ activity reflects the acid-base balance within blood Determines acid-base disorders caused by several pathologic conditions (renal, gastro inadequacy) pCO2 -CO2 is a product of normal metabolism, is released into the blood where it is transported to the kidneys and lungs for excretion Change reflect respiratory status pO2-O2 is essential for cell and tissue metabolism in the body; transported to cells by cardiopulmonary system Measures efficiency of pulmonary gas exchange Evaluates degree of hypoxemia (deficiency of oxygen in arterial blood)

Answer 14

lamp light goes through lens and filter, trasmitted through fibre optic cable, mirrors will focus and direct light into sample chamber, through the cable to the polychromator, light will be diverted to photodiode, the polychromator will seperate light into wavelengths and measure at each wavelength. It will be converted to electrical reading . Wave length calibrator has neon lamp which will emit a stable emission spectrum to test polychromator alignment

Answer 15

Amperometry -applying voltage to an electrode and then measuring the current generated Conductance is the readiness with which a conducting substance transmits electrical current

Answer 16

aspirates the sample and transports them to the metering station

Week 5 Flashcards

(40 cards)