3Rd Year Clinical Biochem - Practicals

Front 1

What are the steps of Molecular diagnosis of inherited diseases ?

Back 1

1. Isolation of genomic DNA
2. Determination of concentration and purity of the DNA
3. Storage of DNA
4. Mutation detection methods

Front 2

What are the two methods of isolation of genomic DNA ?
How is purity of DNa determined ?
How long can DNA be stored for ?

Back 2

Methods of isolation - 1. Traditional method with removal of proteins and precipitation. 2.Spin column purification (binding to silica and salt elution).
Purity of DNA is determined by the absorption ratio of DNA to that of proteins (Abs260/abs280 --> should be 1.7 to 1.9).
DNA can be stored for months at +4, years at -20C, or ten years at -70C

Front 3

What are two DNA mutation detection methods ?
Give 3 types of PCR techniques.

Back 3

DNA mutation detection - southern blot (with restriction enzymes) and PCR.
PCR --> Standard PCR, Multiplex PCR, Quantitative RT PCR

Front 4

Give 4 components of PCR, give 5 ways to analyze PCR products

Back 4

PCR : Template DNA, Primers, Taq polymerase, dNTPs, buffer.
Analysis of PCR products :
1. Electrophoresis
2. Restriction digestion
3. Hybridization probes (heat stability)
4. Hybridization with allele specific nucleotides
5. MLPA
6. DNA sequencing

Front 5

Give two methods to detect Hb levels

Back 5

1. Hemoglobin cyanide (cyanmethemoglobin) method
2. Sodium lauryl sulphate method

Front 6

What are the steps of Hemiglobin-cyanide method to determine Hb ?

Back 6

K3FeCN(6) transforms hemoglobin to hemiglobin. Then CN- forms hemoglobin-cyanide with the Hi. Color product is measured at 540nm

Front 7

What is the sample for Hb determination and where should you keep the reagent ? Also, what is the reference interval ?

Back 7

The sample is whole blood anticoagulatd with EDTA. K3FeCN(6) reagent should be kept in dark and well-capped. REference interval for this method is 140-180g/L or 120-160g/L(female)

Front 8

What are the two methods to determine Hct ?
What is the sample ?
What is the reference interval ?

Back 8

Two ways - Centrifugation, calculation. Sample - whole blood anticoagulated with EDTA or heparin. Reference - male - 0.38-0.52, female 0.37-0.46

Front 9

How is true Hct achieved with the centrifugation method ?

Back 9

Multiply result by 0.97 as sedminted RBCs enclose 3% trapped plasma

Front 10

What is the procedure of Hct determination using centrifugation method ?
How do you calculate Hct ?

Back 10

1. Mix whole blood
2. Fill glass capillaries, close with wax
3. place into rotor with wax outwards
4. 5minx12,000g
5. Read result on capillary and multiply by 0.97
Hct = (RBCxMCV)/1000

Front 11

1.Procedure for blood drawing
2.procedure for microcapillary blood collection

Back 11

1. positioniong
2. Apply torniquet
3. locate vein
4. clean site with isopropyl alcohol
5.venipuncture
6. insert tubes
7. release torniquet before last tube is filled
8. remove needle
9. apply gauze
10. needle disposal and specimen labeling

Microcapillary :
1. site: usually inger of heel
2. clean with isopropyl alcohol
3. puncture finger off the center and perpendicular to fingerprint lines
4. wipe away 1st drop and then collect blood

Front 12

1. What is the vacutainer used for chemical tests (anticogulant,stopper color)
2. What is the vacutainer used for hematology (anticogulant,stopper color)
3. What is the vacutainer used for hemostasis tests (anticogulant,stopper color)

Back 12

1. Chemical tests - no anticogulant, RED
2. Hematology - EDTA, LAVENDER
3. Hemostasis - Sodium citrate, BLUE

Front 13

4. What is the vacutainer used for flow cytometry and chromsome analysis tests (anticogulant,stopper color)
5. What is the vacutainer used for glucose determination(anticogulant,stopper color)
6. What is the vacutainer used for blood culture (anticogulant,stopper color)

Back 13

4.Sodium/lithium-heparin (inactivates thrombin), GREEN
5. Sodium-fluride, inhibits glyolysis, GRAY
6. ACD(acid-citrate-dextrose), maintains RBC viability, YELLOW

Front 14

Two types of smears

Back 14

1. from non-anticogulated blood --> free of artefacts due to storage and the effects of the anticogulant but show plt aggregation
2. From EDTA-anticogulated blood, must be spread within an hour after venipuncture and do not show plt aggregation. Plt morphology can be assessed

Front 15

Steps in preparing a blood smear

Back 15

1. Spreading
2. Fixation in absolut methanol for 5min
3. Stain with Pappenheim panoptic stain based on a May-grunwald-giemsa staining. Nucleic acids and basophilic granules are blue, hemoglobin and eosinophilic granules are red

Front 16

Give two names of the counting chamber ? What is the sample used for cell counting ?

Back 16

Burker counting chamber of hemocytometer. Sample - capillary blood or venous EDTA anticogulated blood

Front 17

What is the process of cell counting ?

Back 17

1. Prepare the sample (20x dilution with Turks solution, mix, discard first drops and fill cell)
2. Set microscope to x100
3. count 4 1mmSquare area (equal to 0.4microliter)
4. Then, if diulted 20x --> Resultx2.5x20 divided by 1000 gives you white blood cells in G/L

Front 18

What is the solution used for the cell counting in the practice ? Also, how do you count platelets ?

Back 18

Leuthromb solution (25microliter blood+475leuthromb). Plt - count 10 rectangles --> multiply by 2 for G/L

Front 19

What are the abnormal RBC forms ?

Back 19

1.Normal - 7-8micrometer, round, central pallor
2.Hypochromatic - pale
3. Microcytic
4. Macrocytic
5. Ovalocyte - egg shaped
6. spherocyte - round with little or no central pallor
7. stomatocyte
8. Target cell, codocyte - hemoglobin in center and periphery
9. Teardrop
10. Schistocyte - small cell with at least one irregular edge
11. Sickle cell - Drepanocyte
12. Echinocyte - regular projections
13. Achantocyte - irregular spiny projections

Front 20

What are the inclusions that can be seen in RBC.
What are the two methods to determine reiculocyte count ?

Back 20

1. Basophilic stipling - dneatured RNA
2. Howell-joly bodies - nuclear remnants
3. Malaria parasites
Reticulocyte count :
1. Brilliant-cresyl blue method
2. Hematology analyzers

Front 21

What are the principles of reticulocyte counting using BCB method, and what is the sample used.

Back 21

Residual RNA can be visualized as fine granulated net by BCB labeling. A cell is a reticulyte if it shows at lesat 2 granules. As reticulocyte count is usually <2%, at least 1000 RBCs need to be counted.
Sample is EDTA-anticoagulated blood

Front 22

What is the procedure of reticulocyte counting by BCB ? What is the principle of counting reticulocytes using hematology analyzers ?

Back 22

1:1 ratio of BCB to blood, mix, wait 60min. Draw smear, use immersion oil to count 1000 RBC. 2 or more granles is a reticulocyte. Principle of hematology analyzers - mature RBCs do not contain nucleic acids while reticulocye have ribosomes and RNA - therefore using fluorescence dye bound to residual RNA immaturaity can be visualized.

Front 23

What is the test sample used in reticulocyte count by hematology analyzer, what is the duration of the measurement and how many cells are counteed ? Also, what is the clinical relevance ?

Back 23

Sample - EDTA anti-coagulated blood
Duration - 10 sec
Cells - 40,000
Clinical - EPO treatment or iron-deficient anemia therapy

Front 24

What is the coeffient of variation for hematology analyzers comparing to manual cell counting ?
Also, what are the 2 methods employed by hematology analyzers ?

Back 24

Manual - 12-20%, Analyzers - <3%
1. Detection of electrical impedence --> Coulter
2. Based on scatter properties

Front 25

What is the general rule in case of maturation of lympoid/myeloid cells ?

Back 25

As cels mature --> cell size and nucleus/plasma ratio decrease. Nucleoli disappear, chromatin condenses and granules and/or shape of mature nucleus are attained

Front 26

How do you differentiate the differnt cells of the myeloid (neutrophilic) lineage ?

Back 26

Myeloblast --> >10micrometer, basophilic, no granulation, loose chromatin, many nucleoli, halo around nucleus
Promyelocyte - Largest in sequence, many azurophilic granules, decreased nucleus/plasma ratio
Myelocyte - less basophilic cytoplasm with less granules and no nucleoli
Metamyelocyte - specific granules appear and nucleus is bean shaped
Band - S shaped nucleus, grayish-blue granulation
Neutrophil - several lobes of nucleus connected, bluish granulation

Front 27

How do you differentiate the cells of the lymphoid line ?

Back 27

Lymphoblast - large nucleus/plasma ratio, purple plasma with nucleoli - similar to myeloblast
Small lymphocyte - small, 10-12micro, basophilic cytoplasm, condensed purple nucleus
LArge lymphocyte - loose chromatin, less basophilic cytoplasm

Front 28

1.MPO is used to diff. between ?
2. Sudan black detects ?
3. Non-specific esterase is used for ?
4. PAS is good for ?

Back 28

1. MPO-->myeloid cells from promyelocytic phase. Grayish-black, diff between AML and ALL
2. Sudan black-->detects phospholipids in myeloid cells
3. NSE - Monocytes and promyelocytes. Sodium-flurid inhibits the reaction only in monocytes
4. PAS - normal granulocytes and pathological lymphoid and erythroid cells are stronlgy positive

Front 29

1. Lysosime is good for ?
2. Prussian blue?
3. GAPA ?
4. Acid phosphatase ?

Back 29

1. Lysosime --> monoblasts and immature monocytes
2. Prussian blue --> positive in ring sideroblasts in MDS
3. GAPA - Low in CGL, however in other myeloproliferative disorders and leukemoid reactions it is positive
4. Acid phosphatase - Lymphoblasts of T origin, myeloma cells, and HCL as part of TRAP. Positive is red.

Front 30

1. Which AML shows NSE ?
2. Which AML shows MPO ?
3. Which AML shows sudan black ?
4. Which AML shows lyosyme ?

Back 30

1. NSE --> AML M3-4-5
2. MPO --> strongest in M3, but in theory all AMLs
3. Sudan black - AML M1-M5
4. Lysosyme - AML M5 (maybe M4)

Front 31

1. What is the precentage of CD34 in the BM of healthy people ?
2. What are 4 possibilites for using immunophenotyping and flow cytometry in leukemia diagnosis

Back 31

1. <5%
2. 1-Analysis of subgroups of leukemias
2. Precentages of lymphocytes,granulocytes, monocytes
3. CD4/CD8 ratio
4. CD34+ stem cells precentage in BM

Front 32

In the bedside test for ABO, how long do you wait ?
How long in the lab method ?
How much do you tilt the sample ?

Back 32

Bedside - wait 30 sec
Lab - wait 10min
Tilt 30degrees

Front 33

What are the possible sources of error in the lab ABO test (left, right, FP, FN)

Back 33

Right side - patients' serum :
1. FP : Unclean instruments, bacterial contamination
2. FN : Did not follow protocol

Left side - Patient's RBCs :
1. FP : same
2. FN : Same
3. Weak or missing agglutination - bad control sera

Front 34

What is the process for RhD determination by Albumin reagent ?

Back 34

1. Temperature should be 37-42C
2. After mixing, put in wet chamber at 37C for 20min
3. Read results in 2-3min

Front 35

What is the process for RhD determination by Papain ?

Back 35

1. Use 1% papain solution
2. use 50% suspension of RBC in its own serum
3. Place in wet chamber for 15 min

Front 36

What are the sample used for PT time, what is the sample preparation process, what are the 2 types of coagulometers used ?

Back 36

1. Sample : tube containing 0.105M sodium citrate in a 9:1 ratio (!). Test within 2 hours.
2. Sample preperation - to obtain plt poor plasma, centrifuge samples at 1500g for 15min at room temp. Use only upper 3/4 of solution (plt poor).
3. Two types of coagulometers - Magnetic sensor coagulometer, turbidimetric, nephelometric coagulometers

Front 37

What is the reagent for the PT time determination ? what is the control value, what is a prolonged time ? how do you interpert the results ?

Back 37

Reagent - Thromboplastin reagent (containing Ca2+ and tissue thromboplastin (TF)). Control value is the mean of PT of healty donors, and is 8-12sec in our lab. Prolonged is >4sec longer. Report results as PT if healty patient or as INR if on oral anticoagulant (comuarin, warfarin)

Front 38

What is the sample for APTT ? What is the sample preparation process ? What does the reagent contain ? what does the starter pipette add ? when do you incubate ? What is the control value for APTT, what is prolonged ?

Back 38

Sample and sample preparation is the same as PT. Reagent contains Phospholipids. Starter pipette puts in CaCl2 (Calcium..), Incubate after APTT reagent and before CaCl2. Control is 28-40 in our lab, prolonged is more than 9sec longer

Front 39

Thrombin time : sample, sample preparation, what does reagent contain, how is the buffer called, what is control, what is prolonged

Back 39

Sample, sample preparation is like PT, APTT. Reagent contains Thrombin, Buffer is called Owren buffer. Control time is 14-22sec, longer is >8sec

Front 40

Principle of Fibrin Monomer(FM) Test

Back 40

Formed during intravascular activation of coagulation. In the reagent FM are coupled to human RBCs (O-) and if FM are present in plasma, hemagglutination will occur. A fast and specific method

Front 41

D-dimer : what method are possible, what is their bases

Back 41

Semiquantitative and quantitative methods. All are based on immunological detection of D-dimer.

Front 42

D-Dimer : what is the sample, what is the principle of the immunological methods, when do you read the results, what is the result if positive, what if negative. What can give FP results.

Back 42

Sample - same as TP/ATTP/TT. Principle - reagent contains latex conjugated specific Ab against D-dimer domain of cross-linked fibrin. The results are read at the 3rd min after mixing. If positive (agglutination), D-dimer >2mg/L, if negative <0.25mg/L. FP results --> RF in plasma

Front 43

Bleeding time - when do you wipe the blood, what is the reference, what is the maximum time, how much pressure do you apply on the tourniquet

Back 43

Wipe every 30sec, refernce 2.5-9.5min, Maximum time is 20min, 40mmHg

Front 44

What are the possible methods for determining Urea cc ?

Back 44

a. Direct chemical methods (old)
b. Indirect enzymatic method :
1. determining NH4+ formation from urea using Urease
2.enzymatic UV kinetic method (NH4 is furhter degraded by GLDH, consuming NADH which decrease is measured)
3.Conductometric method
4.Ionselective electrode

Front 45

What are the possible methods for determining Creatinine cc ?

Back 45

A. Methods based on Jaffe reaction : 1.Endpoint Jaffe reaction, 2.Kinetic Jaffe reaction
B. Enzymatic methods : 1.Partly enzymatic, 2.Completely enzymatic UV

Front 46

What is the principle of the Jaffe reaction for Creatinin ?
What is the process of the Kinetic Jaffe reaction ? What gives falsely high and falsely low results ?

Back 46

-Creatnine in alkaline solution gives an orange product with Picric acid. In simple End-point jaffe reaction we must perform deproteinisation to ensure specificity.
Kinetic Jaffe - Fast, can be easily automated. Creatinine is only measured from 30sec to 2min to avoid interference by other component (proteins, glucose, ketos). Falsely high - ketone bodies (DKA), falesely low - bilirubin

Front 47

What is the process of the enzymatic methods of creatinine determination ?

Back 47

Partyl enzymatic method - creatinine is degraded to ammonia by creatinine aminohydrolate. The ammonia is detected by ionselective electrode.
Completely enzymatic - creatinine is converted to creatine by creatine hydrolase, and this is further detected by reactin with Creatin Kinase

Front 48

Which urine sample types are there ? Which sample is most preffered ? when do you use collected urine ?

Back 48

1. Random
2. First morning urine
3. Collected , 24h.
Preffered sample is first-morning urine (concentrated, acidic). Collected urine is used for clearance, proteinuria

Front 49

How long can urine be kept ?

Back 49

It is recommened that urinalysis and sediment be done within 30min. Urine can be kept for 2 hours at +4C

Front 50

For how long do you submerge urine test strips into the urine ? when do oyu read the results ? what is the bases of the test-strips ?

Back 50

Dip for 1-2sec, read after 1min, bases is dry-chemical reactions

Front 51

Urine specific gravity (reagent, reference range)
Urine pH (indicator, normal range, special)
White blood cells (indicator, principle)

Back 51

Specific gravity - cations cause color change of the bromothymicblue indicator. Ref 1005-1030.
URine pH - Methyl Red, Bromothymicblue. Normal pH 5-6. Vageterians may have higher values.
WBC - Esterase enzyme in granulocytes cleaves indoxylester into indoxyl which forms a purple dye with diazonium. Normal is no color.

Front 52

Urine nitrite (principle, indicator). Urine protein (indictaor, principle). Urine glucose

Back 52

Bacteria in urine turn nitrate into nitrite which can be visualized by hte Griess probe. Protein --> bromophenoblue indicator is set to acidic pH by a buffer, where it is yellow. In the presence of proteins it switches into green-blue depending on cc. Quantiative determination ca be done using the Biuret reaction (?). Urine glucose --> GOD-POD reaction, should be totally negative in urine.

Front 53

Urine ketone bodies (principal, can not detect). UBG (important to..., indicator). Bilirubin (indicator, store sample in..). Blood (indicator)

Back 53

Keton bodies - Principle is Legal probe, use Nitropussid Na. Detects only Acetone and Acetoacetate. UBG --> wait till the sample cools off, diazoniumsaltt forms a red color azo dye with UBG. Store sample in dark.
Bilirubin --> Transformation of diaoniumsalt into colored substance. Store in dark. Blood --> hemoglobin catalyzes the oxidation of tetramethylbenzidine.

Front 54

Urine sediment analysis - where and how do you count casts, where and how do you count cells and other elements. What is the normal range of sediment components in adults ?

Back 54

Casts - 10 LPF with 10-20x objective. Cells, other - 10-20 HPF at 40x objective. Bacteria - semiquantitative.
Normal range in adults - 1 RBC, 1-2 WBC, 1 superficial urothelium per 4-5HPF

Front 55

Which epithelial cells can be found in urine sediment ?

Back 55

Tubular epithel - larger than leukocytes (13micron). Round cells, large nucleus. Appear during fever and ATN. Urothelium - large (30micron), round, usually mononucleated cells. SC epithelial cells - polygonal large (50-60micron) with central small nucleus, usually from contamination with vaginal cells

Front 56

Name the base of urine casts, and 3 types

Back 56

Cylinidrcal shape, formed in the distal tubules. Base matrix is Tamm-Horsfall proteins. Final composition is dependant on pH and presence of components in urine.
Hyaline casts - only Tamm-Horsfall. Fatty casts, Hemoglobin casts (brown color, from eryhtrocyte casts)

Front 57

Name the urine sediment crystals and their shape

Back 57

Cysteine - hexagonal plates
Uric acid - barrel or rosttes
Calcium oxalate - envelope
Triple phosphate (struvite) - coffin-lid

Front 58

Name 3 methods to determine Na, K cc. Two possible false results.

Back 58

1. Atomic absorption (only reference)
2. Flame photometry : ref range Na 135-145, K 3.6-5mmol/L
3. Ionselective electrod ISE: ref range Na 137-150, K 3.5-5.3.
False results : Hemolysis --> increased potassium. Stored blood sample - even without hemolysis, plasma in contact with cells will render their membranes defective leading to increase in K --> this tendency increases in cold !!

Front 59

When can pseudohyponatremia occur ?

Back 59

With a hyperlipemic or hyperproteinemic sample measured by flame photometry or indirect potentiometry (diluted !)

Front 60

Name 2 lab assays for determination of blood glucose

Back 60

1. GOD-POD-PAP assay (Trinder)
2. Hexokinase asasy

Front 61

What is the principle of the Trider method for blood glucose, how is the glucose calculated, what is the ref range

Back 61

Principle is that glucose is convereted to gluconic acid by GOD and also H2O2 is formed. H2O2 reacts with PAra-Amino-PHenazone and Peroxidase to form a color product. Glucose is calclued by the (Sample(abs)/Standard(abs))x7.9. Ref range is 3.6-6mmol/L (maximum is 30mmol/L, more than that have to dilute first)

Front 62

Sources of error in Trinder method for blood glucose (falsely high(also prevention), low)

Back 62

Falsely low - glucose level may decrease by 5%/h if plasma or serum is not seperated from cells of blood within 2h. Glycolysis can be preented by using Sodium Fluoride containing tubes. Falsely high - if a sample is lipemic and serum blank is not substracted from result.

Front 63

What is the diff in glucose values obtained from whole blood using home devices ? Can home devices be used to diagnose DM ? What is the principle of home devices ?

Back 63

Whole blood glucose is 12% lower (due to water content). Home devices cannot be used for dx, only for monitoring. Home devices (test-strips) use either a colour scale or a reflectance photometer.

Front 64

What are 3 tests used for Urine glucose examination ?

Back 64

Qualtitative tests :
1. Nylander test - detection of reducing substances. In presence of reducing substanes, bismuth is liberated and solution turns black. Non-specific.
2. Reagent strips containing GOD-POD and a chromogen (upper limit 1g/L)
3. Quantitative tests (polarimeter, GOD-POD for 24h collected urine)

Front 65

Two tests for detection of Ketone bodies in urine . FP ?

Back 65

1. Legal test : Na nitroprussid is added to urine and is alkalinated by NaOH till its red. In case of keto bodies in urine the color does not change. If they are not present the color fades (!).
2. Reagent strips based on the Legal test. FP --> presence of phenylketones or L-DOPA

Front 66

What is the visual effects of the differnt lipids on serum/plasma ? What are the values ?

Back 66

Serum/plasma are kept at 4C for 24h. CM form a creamy top layer. VLDLs cause turbidity. LDLs and HDL have no effect on visual appearance. If sample is clear ---> Tg<2.5mmol/L. If lightly turbid >2.5mmol/L. If very turbid Tg>6.5mmol/L

Front 67

Steps of Cholesterol assay

Back 67

1. Cholesterol ester + Cholesterol esterase --> Cholesterol + O2 + Cholesterol oxidase --> Cholesterol + H2O2. H202+aminoantipirin + Peroxidase --> Chinoimine (colored).
Also note that another method measures the reduction in oxygen in the cholesterol oxidase reaction.

Front 68

What is the reference range for cholesterol ? What can increase cholesterol values ?

Back 68

There is no ref range for cholesterol. There are risk limits. Risk limit is 5.2mmol/L, treatment is required at >6.8mmol/L.
Chol values are increased by venous compression or standing.

Front 69

Name 3 methods for HDL measurement

Back 69

1. Precipitation of B/PreB lipoproteins by Mg2-Phospho-Wolframate. The HDL reamins in supernatent and can be determined.
2. Ultracentrifugation/Electrophoresis
3. Direct measurement using Polyethylene Glycol (PEG) and anti-apoprotein B/CIII (??)

Front 70

3 methods for LDL calculation, what is the maximum Tg level for the Fridewald calculation to be valid. What are the LDL limits ?

Back 70

1. Friedewald calculation
2. Precipitation of HDL/VLDL by heparing containing agents and measuring the remaining LDL
3. homogenous assays using blocking or solubilization of other classes to achieve specificty of LDL. Limit for Friedewald is 4.5mmol/L Tg.
LDL - <3.4 good, >4.8mmol/L treatment is needed.

Front 71

What is the process for Tg determination ? what are the limits ?

Back 71

Tg + lipase,esterase --> glycerol +ATP +glycerol kinase --> G-3-P.
G3P+02+G3P oxidase --> dihydroxiaceton phosphat+H2O2 +4aminophenazon --> peroxidase -->kinomin (color). ref range : <29year --> <1.35mmol/L
<39year --> <1.68
>40year --> <1.76

Front 72

What is the process of determining total CK ? What is the ref range ?

Back 72

NAC-Activated UV kinetic test.
Presence of CK will create Creatine from creatinphosphate + ATP, the ATP will then be used in a hexokinase reaction that produces G6P which will then be hydrogenized to 6-phosphoglucnate + NADPH. Change from NADP to NADPH is measured. (NADPH absorbs at 340nm). Ref range at 37C is 24-195 U/L

Front 73

What are 3 methods used to determine CK isoenzymes ?

Back 73

1.CK-MB mass concenetration by immunoassay - recommened method, expensive
2. Immuno-inhibition assay : it is assumed there are no CK-BB and macroCKs in the sample. M unit is inhibited and thus CK-MM is inhibited and the only activity measured is of MB (multiply it by 2 !!). Ref range - CK-MB ratio to total CK is 0-6%, CK-MB<24 U/L.
3. Electrophoresis-densitometry (slow, reliable, less quantitative)

Front 74

Which CK isoFORMS are characteristic of MI ?

Back 74

CK-MB2, CK-MM3 - no post-translational lysine cleavage of the C terminal

Front 75

What is the principal of LDH measurement in MI ?

Back 75

LD catalyzes pyruvate to lactate while converting NADH To NAD. Absorbance decrease is measured at 340nm. Ref - 230-460U/L.
Also - electrophoresis for the LDH flip phenomenon

Front 76

Myoglobin as an MI marker, Troponins as an MI marker

Back 76

Myoglobin - rises 2h after, decays within 10-16h. Sensitive, non-specific.
Troponins - Most cardiac specific is cTnI. Troponins can be elevated in kidney failure and heart failure.
Both troponins and myoglobin can be checked by immunochemical assays.

Front 77

Name 4 methods for determination of serum bilirubin

Back 77

1. Direct spectrophotometry
2. Jendrassik-Grof method
3. HPLC
4. Dry chemistry method

Front 78

What is the principle of the direct spectrophotometry method for serum Bilirubin ?

Back 78

Bilirubin absorbs at 455nm (if oxyhemoglobin interefes measure it at 575 and substract) -- can only be used in newborns which do not yet have other interfering compounds in their plasma.

Front 79

What is the principle of the Jendrassik-Grof method of serum bilirubin ?

Back 79

Bilirubin reacting with a diazo-sulfanyylic acid is transformed to a color product called Azobilirubin which is measured at 580nm. Conjugated bilirubin directly reacts with the diazo-sulfanylic acid while unconjugated only in the presennce of coffein. Reference < 20microMol/L

Front 80

Which two tests are used to determine urine bilirubin ?

Back 80

1. Rosin test - a green ring is visible if bilirubin is present
2. EL-U-Test strip - reaction of bilirubin and diasonium salt immersed onto the strip test. Check color after 1 min (!!) after dipping.

Front 81

Which two tests are available to determine urine UBG ?

Back 81

1. Ehrlich's reaction
2. EL-U-Test strip

Front 82

What is the process of the Ehrlich's reaction for measuring urine UBG ?

Back 82

Let urine cool down first, use fresh urine. Ehrlich's reagent is p-dimethyl Amino-benzaldehide. UBG and stercobilinogen form an intense red color with Ehrlich's reagent.

Front 83

What is the principle of the EL-U-Test strip for urine UBG ? What are the normal values of UBG in urine ?

Back 83

UBG reacts with a diasonium salt resulting ina red color azo-dye. Check color after 1 min.
Ref : >1.7micromol/L normal, borderline >17micromol/L, pathological >68micromol/L