proper blanking to elminiate extraneous absorbances

checking components are within acceptable limits

calibrating variables that effect readings

using a blank to "zero out" spectrophotometer

final reading indicates light difference that is absrobed between sample and blank

hemolysis

lipmeic samples

icteric samples

release of hemoglobin and other intracellular components following damage or disruption

autoimmune hemolytic anemia

hemoglobinopathies

drugs

severe infections

patient's condition and lifestyle

phleobotomy skill

local environment

Tests Affected by Hemolysis

-Higher Results

ALT & AST

creatinine

creatinine kinase

iron

LDH

lipase

magnesium

phosphorus

potassium

urea

Tests Affected by Hemolysis

-Lower Results

albumin

chloride

sodium

GGT

glucose

milky our cloudy sample

caused by fatty substances (lipid)

bacteria could also factor

generally why a fasting is done

bright yellow serium

caused by liver disease

hemolytic disorders

assay calls for 100ul of sample with 5ml of reagent

1)replace reagent with water and add 100ul sample - note absorbance reading

2)zero out

3)measure sample now with reagent in it

4)substract blank absorbance from measured sample absorance

select wavelength where minimal photons are emitted

400nm for tungsten-halogen lamp

fill cuvette with distilled water, shoud read 100%T or 0 absorbance

making sure that light emitted is same as wavelength as indicated on dial

use holmium oxide or didymium filters

if observed absorbance doesn't mwatch, dial must be adjusted

use holmium oxide or didymium filter

two absorption peaks are chosen that differ in wavelength by 1 bandpass

common cause is warping of exit slit or surface of the monochromator

check by reading absorbance of a colored solution

clean, unscratched cuvettes should give consistent results

stray light is any light no generated by the light source

caused by misplaced cover or cracked chassis

neutral density filters used to check linearity response as they have known absorbance