CRYSTAL IDENTIFICATION Flashcards
Causes of crystal formation:
a. Metabolic disorders
b. Decreased renal excretion that produces increased blood levels of crystallizing chemicals
c. Degeneration of cartilage and bones
d. Injection of medications (corticosteroid)
Ideally, crystal examination should be performed ____ after fluid collection to ensure that crystals are not affected by changes in ____ and ___
soon
temperature and pH
Both ____ and ____ crystals are reported as being located ___ and ___
(within neutrophils); therefore, fluid must be examined ____ WBC disintegration.
MSU and CPPD
extracellularly and intracellularly
before
are usually located within
vacuoles of the neutrophils while
CPPD crystals
lyse phagosome membranes and therefore do not appear in vacuoles
MSU crystals
Crystals may be observed in
Wright-stained smear
detects the presence or absence of birefringence
Polarizing microscope
confirms the type of birefringence (positive or negative)
Compensated Polarizing Microscope
A ____ compensator is placed between the crystal and analyzer
red
Parallel- Negative Birefringence
Yellow
Perpendicular- Positive Birefringence
Blue
Control slide for the polarization properties of MSU (monosodium urates) can be prepared using
betamethasone acetate corticosteroid
Why should specimens for crystal analysis should not be refrigerated
because they can produce additional crystals that can interfere with the identification of significant crystals.
Why should you avoid using powdered anticoagulant
because it can cause artifacts and may interfere with crystal identification
Monosodium urate
Shape:
Compensated Polarized Light:
Significance:
Shape: Fine Needles
Compensated Polarized Light: Negative birefringence
Significance: Gout
