I.
Introduction
a. The role of laboratory testing in the optometric practice
b. Clinical Laboratory Improvement Amendments (CLIA) regulations
c. Occupational Safety and Health Administration (OSHA) guidelines
d. Applicable practice management of the procedures will be discussed
e. Informed consent considerations may be required
II. General Instrumentation and Supplies
a. Sharps containers
b. Biohazard bags
c. Alcohol prep pads
d. Hand sanitizer
e. Gloves
f. Eye protection
III.Station 1: Erythrocyte Sedimentation Rate (ESR) using Westergren method
a. CPT: 85652QW, Average reimbursement 2009 $4.96
b. Instrumentation
i. Gloves
ii. Eye protection
iii. Fresh whole blood samples (2-5 ml venous blood) in lavender-topped tubes
containing ETDA will be collected before workshop begins
iv. ESR kit, including
1.Dispette tube
2.Transfer pipette
3.Reservoir
4.Tube stand
c. Procedure
i. Put on gloves and eye protection on
ii. Remove cap from blood sample tube and the reservoir tube. Use the transfer
pipette to transfer blood into the reservoir up to the fill line. Replace the cap on
the reservoir tube and properly discard of the blood sample and pipette tube.
iii. Carefully, but forcefully push the Dispette tube into the top of the reservoir,
penetrating its cap membrane. Push the tube all the way to the bottom of the
reservoir so that the blood is forced to the top of the Dispette tube.
iv. Ensure that the Dispette tube sits at an angle of 90˚, ±1˚. Let stand for one
hour, then measure the ESR.
d. Indications
i. Elevated in cases of acute inflammation or infection
ii. Signs or symptoms of giant cell arteritis-STAT
iii. Recalcitrant ocular inflammation without known cause
iv. Signs of inflammatory autoimmune disorder
e. Expected results
i. Males: age/2
ii. Females: (age + 10)/2
f. Other
i. Wintrobe ESR
ii. C-reactive protein
1.alternative and/or supplemental to ESR
2.more sensitive: elevated more quickly in inflammation but disappears more
rapidly with resolution
IV. Station 2: Blood glucose and Glycosylated Hemoglobin (Hb A1c)
a. Elevated in diabetes and other causes of hyperglycemia
b.
Glucometry using finger stick method
i. CPT: 82962QW, Average reimbursement 2009 $3.42
ii. Indications
1.Suspected hyperglycemia or hypoglycemia
2.Retinal hemorrhages
3.Unexplained refractive shift
4.Known diabetes with suspected acute diabetic crisis
iii. Instrumentation and Procedure
1.Glucometer such as Accu Check, Glucometer or Stat Tek
2.Venous blood sample from finger stick
3.Lancet
iv. Expected results for non-diabetic patient
1.Fasting: 70-105 mg/dl
v. Recommended results for diabetic patients
1.A1c: <7.0%
2.Preprandial capillary plasma glucose: 90-130 mg/dl
3.Peak postprandial capillary plasma glucose: <180 mg/dl
vi. Critical values:
1.Males: <50 mg/dl
2.Females: <40 mg/dl
3.>400 mg/dl
vii. Clinical pearls
1.Fasting: 8-12 hours before collection
2.2006 ADA criteria for diagnosis of diabetes:
1. Symptoms of diabetes and casual plasma glucose ≥200mg/dl
2. OR: Fasting plasma glucose of ≥126 mg/dl (preferred method of
testing)
3. OR: A 2-hr plasma glucose of 200mg/dl during a glucose tolerance
test
c.
Hemoglobin A1c/Glycosylated hemoglobin for finger stick method
i. CPT: 83037QW, Average reimbursement 2009 $18
ii. Indications
1.Known diabetes with unknown compliance
2.Known diabetes with suspected acute diabetic crisis
3.Suspected diabetes
iii. Instrumentation and Procedure
1.A1c Now Multitest Kit (Metrika/Bayer)
2.Venous blood sample from finger stick
3.Lancet
iv. Expected results (percentage of total Hb)
1.5.5-8.8%
2.Recommended value for diabetics by ADA: 6-7%
v. Critical values:
1.Ketoacidosis: 14.3-20%
vi. Clinical pearls
1.“Falsely” low with chronic kidney disease patients
2.estimated Average Glucose (eAG): formula that converts A1c reading to
mg/dL
3.A1c Now also available for at-home testing: finger stick and mail in form to
lab
1. Other products for at-home testing include FlexSite A1c At-home Test,
Landmark Diagnostics
V. Station 3: Rapid pathogen screening (RPS) and Conjunctival Swabbing
a. Rapid pathogen screening (RPS): Adenovirus detector
i. CPT: 87809QW, Average reimbursement 2009 $17.52
ii. Indications
1.Acute red eye with unknown cause
2.Suspected adenovirus
3.Acute red eye in child, mentally handicapped or other non-verbal patient
iii. Instrumentation and Procedure
1.RPS Adeno detector kit
iv. Future of conjunctivitis diagnosis
1.Herpes Simplex
2.IgE
3.Chlamydia
b. Conjunctival Swabbing
i. Indications
1.Mucopurulent discharge with unknown cause
2.Recalcitrant red eye
3.Suspected Chlamydial conjunctivitis (requires specific medium/swab kit)
ii. Instrumentation
1.Culturette/Sterile swab kits with transport medium
1. Stuart medium
2. Amies with charcoal
3. Amies without charcoal: higher yield than other culturettes
(comparable to plating)
iii. Some of the methods used for suspected Chlamydial conjunctivitis
1.Cell culture (CPT: 87110QW, $27 average reimbursement): 2-3 day
incubation period, looking for inclusion bodies; 100% specificity
2.Enzyme-linked immunoassay test kits: detects antigen in clinical specimen
swab kit for C. trachomatis; includes Chlamydiazyme (Abbott Laboratories);
viable organism not necessary to run test—not required to process swab
immediately; phosphate transport medium is used
3.Rapid Immunoassay test kits: Clearview, Kodak Surecell Chlamydia, Abbott
TestPack Chlamydia
4.Direct Fluorescent Antibody (CPT: 87270QW): uses methonal solution to
fixate cell sample to slide
5.Nucleic Acid Amplification (CPT: 87270QW): requires swab or urine sample
VI. Station 4: Macroscopic Urinalysis (dipstick method)
a. CPT: 81002QW, Average reimbursement 2009 $4.37
b. Indications
i. Pregnancy testing
1.Refractive shifts
ii. Ketone levels: elevated in diabetics, ketoacidosis, alcoholism, glycogen storage
diseases
1.Refractive shifts
2.Retinopathy without a correlating history
3.Suspected nutritional or toxic amblyopia
iii. Proteinuria
1.sarcoidosis, systemic lupus erythematosus, Fabry’s disease, malignancies
iv. Others
1.Suspected galactosemia cataracts: albumin in urine
2.Homocystinuria
c. Instrumentation and Procedure for Dipstick Urinalysis
i. Urinalysis dipstick kit
ii. Urine sample: fresh (tested with 30min unless kept on ice), 2-10ml sample
iii. Properties observed and measured
1.Physical observation
1. Color
i. Dark amber: non-dilute
ii. Colorless/clear: dilute
iii. Other colors caused by food/drugs ingensted
2. Odor (i.e. Sweet smelling: ketoacidosis)
3. Turbidity: turbid urine may indicate infection
2.Specific gravity—compares weight of urine to that of distilled water (1.0)
1. Normal result: 1.003-1.030
2. If elevated: non-dilute due to extra solid components (i.e. urea, NaCl,
protein, glucose, drug metabolites)
3. If reduced: urine is dilute
3.pH
1. normal: 5.0-8.4
2. alkaline shift (9.0) may indicate infection (i.e. UTI)
4.Contents
1. glucose: amount in urine depends on renal threshold for retention;
most people’s spillover is approximately 180mg/dl; when elevated,
must rule out diabetes
2. ketones: produced from the metabolism of fatty acids, may indicate
diabetic ketoacidosis, starvation, fever, drug toxicity
3. protein: 99% reabsorbed normally; albumin is the primary component
of urinary protein (others may be present); elevated in renal disease,
hypertensive nephropathy
4. blood: if detected visually, may be due to urinary disease (bright red)
or renal disease (darker); drugs, many other possible causes
5. nitrites: certain bacteria can convert nitrate to nitrite; presence may
indicate infection; negative result does not rule-out infection
6. leukocytes: infection, typically UTI
7. bilirubin: formed in spleen and bone marrow from breakdown of
hemoglobin; elevation may indicate liver disorder, hepatitis
8. urobilinogen: bilirubin is broken down into urobilinogen by certain
bacteria in intestines; trace amounts are normal in healthy patients;
elevation may indicate liver disease/infection (i.e. jaundice, cirrhosis);
reduction may be secondary to toxicity from drugs that inhibit certain
bacteria in GI system (i.e. chloramphenicol)
VII.
Useful resources
a. Cms.hhs.gov/CLIA/downloads
b. OSHA.gov