1- intro clinical biochem

8/11/2019 1- Intro Clinical Biochem

1/38

INTRODUCTIONTO CLINICAL

BIOCHEMISTRYLAB


2/38

OBJECTIVE

Students are expected to:

Explain types of biochemistry test with examples.

Describe types of specimen available.

Understanding sources of sampling error. Explain the factors contributing variation of results.

Understanding the importance of the Clinicalbiochemistry lab.

Expecting General Risk

Describe Clinical Biochemistry Process

Elaborate Quality Assurance (QA) & Quality Control(QC)


3/38


4/38


5/38

Types of Specimen

Blood

Serum- blood which is collected into plain tube that allowed toclot in room temp.

- recommended for biochemical analysis

Plasma- used when the analyte questioned is unstable- obtained when blood collected in an anticoagulant tube

- when centrifuged, the supernatant is called plasma

Urine Cerebrospinal fluid

Others?


6/38

SPECIMEN COLLECTION The test request

The specimen for analysis must be collected andtransported to the laboratory according to a specified

procedure if the data are to be of clinical value. This

procedure begins with the clinician making a test

request, either on a computer terminal or on paper. Thecompleted request should include:

patient's name, sex and date of birth

hospital or other identification number

ward/clinic/address name of requesting doctor (telephone/pager number for

urgent requests)

clinical diagnosis/problem


7/38

test(s) requested

type of specimen

date and time of sampling

relevant treatment (e.g. drugs).

It is essential that sufficient information be provided

to identify the patient. In practice, vital information is

often omitted and this may either cause delay in

analysis and reporting or make it impossible tointerpret the results.


8/38

Sampling Error Blood sampling technique

-improper technique lead to hemolysis and give falsepositive result with consequent increase of potassiumand red cell constituents.

Prolong stasis during venipuncture- stasis causes plasma water diffuse into interstitialspace and serum or plasma sample obtained will beconcentrated.

- protein and protein bound components of plasma such

as calcium or thyroxine will be falsely elevated

Insufficient specimen

- certain volume of specimen is required to enable the

test to carried out


9/38

Errors in timing

- collection of an accurately time volume of urine such as24 hrs urine

Incorrect specimen storage

- blood sample stored overnight before being sent to labwill show falsely high K+, phosphate and red cellenzymes such as LDH because of leakage into theextracellular fluid (ECF) from the cells.

Inappropriate sampling site

- blood taken downstream from IV drip may affected bythe drip content

Incorrect specimen container

-anticoagulant/ preservative. Eg: glucose in fluoride tubewhich inhibits glycolysis.

-never decanted into another tube.


10/38

Variation Result


11/38

Variation Result

Due to biological factors:

Gender-muscle mass

Age- increase in ALP

Diet-fasting,malnutrition,alcoholic

Pregnancy- insulin resistance

Time the sample taken- cortisol

Stress and anxiety

Medical and drug history


12/38

Importance of Biochemistry Lab

Screening

detection of subclinical disease Diagnosisconfirmation or rejection of

clinical diagnosis

Prognosisinformation regarding the likely

outcome of disease

Monitoringmonitoring progression or

response to treatment


13/38

General Risk in Lab Test

Determination of the right test

- to decide the most sensitive, specific, accurate andprecise with reasonable price

Sample collection procedure

- collected with right manner. Eg: avoid hemolysis duringblood collection

- collected from right source. Eg: CSF to determinemeningitis

Sample transportation- use the right tubes. Eg: tubes with sodium citrate forglucose


14/38

Sample storage

- serum separated from blood cells before storage

- urine should not be left more than 2 hours unless

refrigerated

Human error

- unskilled lab personnel

Interpretation of result

- use the right reference range


15/38

Clinical Biochemistry Process

Clinical questions

Request form & clinical data

Specimen collection

Transit sample to lab

Reception at lab and ID Analysis

QC

Collation

Result interpretation Reporting to doctor

Biochemistry answer


16/38

Quality Assurance (QA) & Quality

Control (QC)

Pre Analytical Quality Assurance

Analytical Quality Assurance

Post Analytical Quality Assurance

Quality Control


17/38

Quality Assurance (QA)

QA - all activities that ensure the validity ofchemical testing and analysis and all relevant

technical support

Lab personnel required to follow QA plans and

SOP

These documents and staff vigilance help

ensure the analytical data and other test results

will be acceptable as the bases for makingsignificant decision.


18/38

Pre Analytical Error

Patient preparation- nutrition status, recent meal, alcohol, drugs, smoking,exercise, stress

Sample collection and handling

- right specimen collection tubes usage

- sample match with anticoagulant or additive

- specimen transportation and separation

- avoid contamination

-effects of infusion

- hemolysis


19/38

Storage

- to know the characteristics of each analyte and store

with right manner in order to preserve the analyteamount

- Evaporated analyte to store with tightly capped. Eg:

electrolytes

- Light sensitive analyte to be stored in dark place. Eg:bilirubin

- Temperature sensitive analyte to be refrigerated. Eg:

Lactate dehydrogenase


20/38


21/38

Post Analytical QA

System to record all patients profile to avoidlosing data

System to report the reliable lab data to the

doctors in specific time given


22/38

Quality Control (QC)

Refers to the measures that must be included

during each test run to verify that the test is

working properly.

Aims to recognize and minimize analyticalerrors.


23/38


24/38

Management requirement ISO 9000

-certification:

-documented quality system is in place

-Auditors are skilled in Quality Assurance but

may not have the expertise in service.

ISO 15189

-more specific for lab operation

-technically competant, have laboratory

experience, skilled in lab management, QA

technique


25/38

ANALYSIS OF BLOOD

BIOCHEMISTRY
http://rds.yahoo.com/_ylt=A0S020yS4UhKgOYA8lijzbkF/SIG=12lpglmue/EXP=1246376722/**http%3A//www.sandhurstjoggers.org.uk/3-HealthAdvice/blood_cells.jpg


26/38

Learning objectives:

Describe blood composition

Differentiate types of blood sample and its

source

Explain causes lead to hemolysis and how to

avoid hemolysis

Identify the blood collection tubes and the

usage of the tubes


27/38

Blood Composition

Cells

Erythrocytes

Leucocytes

Platelet

Plasma vs serum?? - nutrient, metabolism

product


28/38

Plasma vs serum


29/38


30/38

Hemolysis Due to - high speed centrifugation

- high pressure during draw the blood

Hemolysis avoided by: Use dry and clean needle and syringe

Apply minimal constriction on arm

Let blood flow slowly into syringe

Use dry blood tube Mix well blood with anticoagulant

Low velocity centrifugation


31/38

Blood Tubes
http://rds.yahoo.com/_ylt=A0S020ov6EhKjEUBHReJzbkF;_ylu=X3oDMTBxdHZyM2NlBHBvcwM4BHNlYwNzcgR2dGlkA0kxMTBfMTMx/SIG=1g6u89oo3/EXP=1246378415/**http%3A//images.search.yahoo.com/images/view%3Fback=http%253A%252F%252Fimages.search.yahoo.com%252Fsearch%252Fimages%253Fp%253Dblood%252Btubes%2526ei%253Dutf-8%2526y%253DSearch%2526fr%253Dyfp-t-501%26w=180%26h=180%26imgurl=www.rgu.ac.uk%252Flife%252Fimages%252Fblood-tubes.jpg%26rurl=http%253A%252F%252Fwww.rgu.ac.uk%252Flife%252Fdefault_text.cfm%26size=23k%26name=blood%2Btubes%2Bjpg%26p=blood%2Btubes%26oid=04e3f9f335859ade%26fr2=%26no=8%26tt=4477%26sigr=11adpd26t%26sigi=1191skn04%26sigb=12pujm8sr


32/38


33/38

St Additi R lti Additi A C t


34/38

Stopper

Colour

Additive Resulting

Sample

Additive

Action

Assay Comments

Grey Na fluoride &

K oxalate

Plasma Inhibit

glycolysis

Glucose,

lactose

Not for Na & K

analysis

Green Na/Li/NH3

Heparin salts

Plasma Enhance

antithrombin

III

Cortico

steroids,

electrolytes

Antithrombin

III inactivates

clotting factors

Brown Na heparin Plasma Enhance

antithrombin

III

Lead Tube has only

minute

quantity of

lead

Royal

blue

None Serum None Trace

elements

Tube has only

minute

quantity of

traceelements

Lavender EDTA Plasma Binds Ca CEA,

hematology

test

Ca is needed

for clotting

Blue Na citrate Plasma Binds Ca Coagulationtest Ca is neededfor clotting


35/38


36/38


37/38


38/38

NEXT CLASS

ACTIVITY 1

Student need to form group of 4 and number

each group member. Propose a procedure on

drawing blood sample and decide on the best

tube used for these situations: a) To monitor blood glucose level

b) To investigate bleeding tendency

c) To determine cardiac enzyme level in

blood

Justify your answer.

1- intro clinical biochem

Documents