2. A medical laboratory is a place where
tests are done on clinical specimens and
samples in order to get information about
the health of a patient as pertaining to
the diagnosis, treatment, and prevention
of disease
Laboratory Services include testing of
materials, tissues or fluids obtained from
a patient or clinical studies to determine
the cause and nature of disease
4. What are Laboratory Services all
about?
Laboratory Services play a critical role in the
detection, diagnosis and treatment of disease. Samples
are collected and examination and analysis of body
fluids, tissue and cells are carried out. Main services
are:
To Perform diagnostic tests
To Identify organisms
To Count and classify blood cells to identify infection
or disease
To Perform immunological tests to check for
antibodies
To Type and cross-match blood samples for
transfusions
To Analyze DNA
7. Principles for Screening Programs
1. There should be a recognizable early or latent
stage
2. There should be an accepted treatment for the
condition
3. The screening test is valid, reliable
4. The test must be acceptable to population to be
screened
5. Cost of screening and case finding should be
economically balanced in relation to medical care
as a whole
9. Check-Up for a 50-Yr Woman
• BP measurement
• Fasting blood glucose
• Fasting lipid profile
• Pap’s smear
• Mammography
• FOBT
– Colonoscopy: F/H of colon Ca
• Vision & hearing
Ref: Harrison's Internal
Medicine
10. Check-Up for a 50-Yr Man
• BP measurement
• Fasting blood glucose
• Fasting lipid profile
• DRE/PSA
• FOBT
– Colonoscopy: F/H of colon Ca
• Vision & hearing
Ref: Harrison's Internal
Medicine
11. Benefits
• A primary goal of screening is the early detection
of a risk factor or disease at a stage when it can
be corrected or cured
• More effective treatment
– Improved quality of life
– Prolongation of survival
12. Adverse Consequences of
Screening
• Not all are evidence-based
• Generates a number of false positive results
– Require further expensive & risky investigations
– Anxiety in patient & family
– Dilemmas in the clinician
13. BASIC SCREENING TESTS
CBC
ECG
Liver function test
Renal function test
Thyroid function test
Electrolytes
Blood sugar
Aim: ruling out organicity
Ref: Kaplan & Sadock's Synopsis
of Psychiatry
14. Principles of endocrine tests
Timing of measurement: Release of many
hormones is rhythmical(pulsatile, circadian,
monthly)random test may be invalid,
sequential/dynamic test may be required.
Choice of dynamic tests:
-If deficiency suspected: stimulation test
-If excess suspected: suppression test
-Avoid interpreting one result in
isolation
Imaging,Biopsy: may be needed
16. Interpretation of TFTs
TSH T4 T3 Interpretation
U.D.
(Undetectable)
Raised Raised Primary thyrotoxicosis
U.D. Normal Raised Primary T3-toxicosis
U.D. Normal Normal Subclinical thyrotoxicosis
U.D. Raised Low,normal
or raised
Sick euthyroidism
Elevated >20
mu/L
Low Low Primary hypothyroidism
Mildly5-20
mu/L
Normal Normal Subclinical hypothyroidism
20-500
mu/L
Normal Normal Artefact
17. Non-specific laboratory abnormalities
in thyroid dysfunction
Thyrotoxicosis:
• Alanine aminotransferase, γ-glutamyl transferase
(GGT), and alkaline phosphatase from liver and bone
• bilirubin
• Mild hypercalcaemia
• Glycosuria
Hypothyroidism:
• Creatine kinase, aspartate aminotransferase, LDH
• Hypercholesterolaemia
• Anaemia
– Normochromic normocytic or macrocytic
• Hyponatraemia
18. Dexamethasone-suppression test
• Indication: Supporting Dx of MDD.
• Procedure: pt is given 1mg of D.methasone
by mouth at 11pm & plasma cortisol is
measured at 8am,4pm,11pm.
• Result: -Nonsuppression:cortisol>5mg/dl
-Suppression: HPA-axis is normal
• Nonsuppression is associated with stress.
• Limitation: False +ve & -ve, Low sensitivity
19. Dexamethasone-suppression test
Importance:
1.+ve DST,Good response to ECT or TCA
2.To differentiate MDD from minor dysphoria
3.Predicting outcome of treatment
4.Predicting relapse:Persistent nonsuppression
5.Differenting delusional from nondelusional
MDD
6.High abnormal cortisol >10µg/dl are more
significant than mildly elevated level
21. Hyperprolactinaemia
• C/F: Male:sex.dysfunction,infertility,breast
growth,bone mineral density.
Female:Amenorrhoea,galactorrhoea
• Monitoring: -ask prolactin-related symptoms
- prolactin level:at prescribing
at 3 months
yearly
• Avoid prolacting-elevating drugs:
-pt under 25yrs –pt with osteoporosis
-pt with H/O breast cancer
22. Hyperprolactinaemia
Prolactin concentration interpretation:
Take blood sample at least one hour after
waking or eating
Minimise stress during venepuncture (stress
elevates plasma prolactin)
Normal : Women :0–25 ng/ml
Men :0–20 ng/ml
Re-test: if prolactin concentration 25–100
ng/ml ( 530–2120 mIU/l)
Referral :to rule out prolactinoma if
prolactin concentration>150 ng/ml (>3180
mIU/l)
24. Hyperprolactinaemia
Treatment:
Switch to a non prolactin-elevating drug
is the first choice
An alternative is to add aripiprazole to
existing treatment
For patients who need to remain on a
prolactin-elevating antipsychotic,dopamine
agonists may be effective Amantadine,
carbergoline and bromocriptine,but each
has the potential to worsen psychosis.
25. Psychiatric Disorders
No laboratory tests in psychiatry can confirm or rule out
diagnoses
Psychiatrists depend more on the history, clinical
examination and MSE to make a diagnosis
• Investigations:
1.Routine:
-FBC, U&Es, LFTs, TFTs,RFTs, RBS,CXR, ECG
2.Special: (if indicated by history or physical signs)
-Urine toxicology
-Antinuclear antibody(SLE)
-Syphilis serology
-CT/MRI, EEG, LP
-HIV testing
27. A1C ≥6.5%
OR
Fasting plasma glucose (FPG)
≥126 mg/dL (7.0 mmol/L)
OR
2-h plasma glucose ≥200 mg/dL
(11.1 mmol/L) during an OGTT
OR
A random plasma glucose ≥200 mg/dL
(11.1 mmol/L)
Criteria for the Diagnosis of Diabetes
ADA. I. Classification and Diagnosis. Diabetes Care 2012;35(suppl 1):S12. Table 2.
28. Criteria for Testing for Diabetes in
Asymptomatic Adult Individuals (1)
• Physical inactivity
• First-degree relative with diabetes
• High-risk race/ethnicity (e.g., African American,
Latino, Native American, Asian American, Pacific
Islander)
• Women who delivered a baby weighing >9 lb or were
diagnosed with GDM
• Hypertension (≥140/90 mmHg or on therapy for
hypertension)
*At-risk BMI may be lower in some ethnic groups.
Testing should be considered in all adults who are
overweight (BMI ≥25 kg/m2*) and who have one or
more additional risk factors:
29. Criteria for Testing for Diabetes in
Asymptomatic Adult Individuals (1)
• HDL cholesterol level
<35 mg/dL (0.90 mmol/L) and/or a
triglyceride level >250 mg/dL (2.82 mmol/L)
• Women with polycystic ovarian syndrome
(PCOS)
• A1C ≥5.7%, IGT, or IFG on previous testing
• Other clinical conditions associated with insulin
resistance (e.g., severe obesity, acanthosis
nigricans)
• History of CVD
*At-risk BMI may be lower in some ethnic groups.
30. 1. In the absence of risk factors testing for
diabetes should begin at age 45 years
2. If results are normal, testing should be
repeated at least at 3-year intervals, with
consideration of more frequent testing
depending on initial results (e.g., those with
prediabetes should be tested yearly), and
risk status
ADA. Testing in Asymptomatic Patients. Diabetes Care 2012;35(suppl 1):S14. Table 4.
Criteria for Testing for Diabetes in
Asymptomatic Adult Individuals (2)
31. Categories of increased risk for
diabetes (prediabetes)
A1C: 5.7%-6.4%
Impaired Fasting Glucose(IFG)
FPG: 5.6-6.9 mmol/L (100-125mg/dl)
Impaired Glucose Tolerance (IGT)
2-h value in OGTT: 7.8-11.0 mmol/L
(140-199mg/dl)
32. Monitoring:Pt receiving
antipsychotics
TIME IDEAL TEST MINIMUM TEST
Base line
OGTT or FPG
HBA1C if fasting not
possible(+RBS)
Urine glucose
RBS
Continuation All Drugs:OGTT or
FPG or HBA1C every
12months (+RBS)
Olanzapine,Clozapine:
OGTT or FPG after 1
month,then every 4-6
months
Urinary glucose or RPG
every 12 months +
symptoms monitoring
33. Risk of DM with antipsychotics
Degree of risk Antipsychotics
High Clozapine,Olanapine
Moderate Quetiapine,Risperidone,Phenothiazines
Low High potency FGAs: Haloperidole
Minimal Aripiprazole,Amisulpride,Asenapine
Ziprasidone
35. Antipsychotics & Dyslipidaemia
FGAs: -Phenothiazines: TG, LDL,HDL
-Haloperidole: minimal effects
SGAs: -Mild: Aripiprazole,Ziprasidone
May even reverse
-Moderate:Risperidone,Quetiapine
-Severe: Olanzapine,Clozapine
36. Monitoring
Antipsychotics drugs Suggested monitoring
Clozapine and Olanzapine Fasting lipid at baseline,then every 3
months for a year,then annually.
Other antipsychotics Fasting lipid at baseline,then at 3
months, then annually.
37. Hyponatraemia
Causes of hyponatraemia Treatment
Water intoxication Monitor serum sodium( as day
progress)
Fluid restriction
Careful use of IVsaline:Rhabdomyolysis
Consider treatment with clozapine
Refer if Na<125 mmol/L
SIADH: Associated with all
antipsychotics
Monitor serum sodium
Fluid restriction
Switch to different antipsychotics
Refer if Na<125 mmol/L
Severe hyperlipidaemia and/or
hyperglycaemia
Pseudohyponatraemia
Treat the cause
38. Antidepressant-induced hyponatraemia
• Most antidepressants have been associated
with hyponatraemia
• Onset:is usually within 30 days of starting
treatment
• not dose-related
• The mechanism:probably the syndrome of
inappropriate secretion of antidiuretic
hormone (SIADH); serotonin is thought to
be involved in the regulation of ADH
release
39. Antidepressant-induced hyponatraemia
MONITORING:
• pt taking antidepressants:observe signs of hyponatraemia
Serum sodium should be determined :at baseline
2 & 4 wks
• and then 3-monthly
those at high risk
The high-risk factors are as follows:
- extreme old age (>80 years)
- history of hyponatraemia
- co-therapy with drugs associated with hyponatraemia
- reduced renal function (GFR <50 ml/min)
- medical co-morbidity
common in elderly patients so monitoring is essential
41. Sexual dysfunction
• Should be arranged according to cause
ED: -FBS
-Testosterone
-SHBG
-LH/FSH
-Prolactin
-Thyroid Function
-PSA
-S. Lipid profile
42. Lab Test: FSAD
• Depends on relevent symptoms
• If low desire suspected along with
arousal: S.Testosterone, SHBG
• If menopausal (vaginal dryness) state
– S. Estrogen
• If comorbid with marked oligomenorrhoea
– S. Prolactin
• Thyriod Status if clinical history suggest
43. NMS
NMS is rare,even fatal outcome of
antipsychotics
Incidence:0.2% of pt taking antipsychotics
Onset: often first 10 days of treatment
Lab findings: - Creatinine phosphokinase
- WBC
- Alter LFT
44. Pre-anaesthetic check prior to
ECT
ECT work-up:-CBC
-ECG
-Liver function test
-Renal function test
-Electrolytes
-Blood sugar
-Vital signs:pulse,BP,tem,RR
-Check no medication or
seizure threshold
45. Rapid tranquillisation
The clinical practice of RT is used to
de-escalate acutely disturbed behaviour
The aims of RT are :
1. To reduce suffering for the patient
2. To reduce risk of harm to others
3. To do no harm
46. RT:monitoring
After any parenteral drug administration, monitor as
follows:
Pulse Blood pressure
Temperature Respiratory rate
Time: Every 5–10 min for 1 hour, and then half-hourly
until patient is ambulatory.
If pt is asleep or unconscious :use pulse oximetry
ECG and haematological monitoring:strongly recommended
when parenteral antipsychotics are given
Hypokalaemia, stress and agitation place the patient at
risk of cardiac arrhythmia
ECG monitoring :for all patients who receive haloperidol.
47. Substances of Abuse That Can
Be Tested in Urine
Substance Length of Time Detected in Urine
Alcohol 7-12 hours
Amphetamine 2 days
Barbiturate 1 day (short-acting)
3 weeks (long-acting)
Benzodiazepine 3 days
Cannabis 3 days to 4 weeks (depending on
use)
Cocaine 6-8 hours (metabolites 2-4 days)
Codeine 2 days
Heroin 36-72 hours
Methadone 3 days
Morphine 2-3 days
48. Plasma level monitoring of
psychotropics
Is there a clinically useful assay method available?
Is the drug at ‘steady state’?
Is the timing of the sample correct?
Is there a target range of plasma levels?
Is there a clear reason for plasma level determination?
Only the following reasons are valid:
– to confirm compliance
– if toxicity is suspected
– if drug interaction is suspected
– if clinical response is difficult to assess directly
– if the drug has a narrow therapeutic index and
toxicity concerns are considerable.
49. Interpreting sample results
Drug Target range Sample timing Time to
steady
state
Aripiprazole 150–210 µg/L Trough 15–16 days
Clozapine 350–500 µg/L Trough 2–3days
Lithium 0.6–1.0 mmol/L
(may be >1.0 mmol/L
in mania)
12 hours post-dose 5-7 days
Olanzapine 20–40 µg/L 12 hours post-dose 1 week
Tricyclics Nortriptyline :50–150
µg/L
Amitriptyline: 100–200
µg/L
Trough 2–3 days
Valproate 50–100 mg/L Trough 2–3 days
50. TCA
Indication for plasma monitoring:
1.To check compliance
2.Toxic side effect at low dose
3.Lack of therapeutic response
4.Doses>200mg
5Coexisting medical illness(e.g.Epilepsy)
6.Possibility of drug interaction
51. Clozapine
Many adverse effects are dose-dependent & more
common at beginning of treatment
Target dose: Average dose is around 450mg/day
Response seen in the range 150–900 mg/day
Plasma levels : Response is in range 350–420 µg/L
Mandatory blood monitoring and registration
- Register with the relevant monitoring service.
-Perform baseline blood tests (WCC and
differentialcount) before starting clozapine.
-first 18 weeks=Weekly
-remainder of the year=2 weekly
-After that= monthly
Stop cloapine: WBC<3000 OR Neutrophil<1500 per
mm3
55. Lithium
On treatment monitoring:
1.Plasma lithium: -First after 7 days
-Then weekly=3weeks
-Once every 6 week
-Then 2-3 months.
2.e-GFR & TFTs : every 6 months
3.BMI
Plasma level: Acute mania: 0.8-1 mmol/L
Prophylactic: 0.5-0.8 mmol/L
Toxicity: >1.5 mmol/L
Narrow therapeutic index: Lithium toxicity
56. Lithium Toxicity
1.Mild to moderate intoxication
(lithium level = 1.5 to 2.0 mEq/
GI Vomiting,Abdominal pain
Neurologic Ataxia,Dizziness,Slurred speech
Nystagmus,Lethargy or excitement
Muscle weakness
2,Moderate to severe intoxication
(lithium level = 2.0 to 2.5 mEq/L)
GI Anorexia
Persistent nausea and vomiting
Neurologic Blurred vision,Muscle fasciculations
Clonic limb movements
tendonreflexes,Convulsions,Delirium,
SyncopeStupor,Coma,Circulatory
failure
3.Severe lithium intoxication
(lithium level >2.5 mEq/L)
Generalized convulsions , Oliguria
renal failure, Death
57. Management of Lithium Toxicity
Lithium must be stoped at once
High intake of fluid,maintenance of electrolyte
balance
Examination :vital signs,neuro. Exam, MSE
Lab:Lithium level,serum electrolytes,RFTs,ECG
Acute ingestion:gastric lavage,activated charcoal
Osmotic or forced alkaline diuresis should be
used . NEVER thiazide or loop diuretics
Lithium level >3.0 mEq/L: haemodialysis
Repeat dialysis :every 6 to 10 hours, until the
lithium level is within nontoxic range
58. Instructions to Pt Taking Lithium
Dosing
Take lithium exactly as directed by your doctore.Do not stop taking without
speaking to your doctor.If you miss a dose, take it as soon as is possible. If it
is within 4 hours of the next dose, skip the missed dose. Never double up
doses.
Blood Tests
Comply with the schedule of recommended regular blood tests.
you should have taken your last lithium dose 12 hours earlier.
Use of Other Medications
Do not start any prescription without telling your doctor
Diet and Fluid Intake
Avoid sudden changes in your diet or fluid intake. If you do go on a diet,
inform your doctor.Caffeine and alcohol act as diuretics and can lower your
lithium concentrations.
it is recommended that you drink about 2 or 3 quarts of fluid daily, and use
normal amounts of salt.
Recognizing Potential Problems
If you engage in vigorous exercise or have an illness that causes sweating,
vomiting, or diarrhea, consult your doctor.Pt is educated about early signs of
lithium toxicity
59. Lithium & eGFR
• Indication for referral to specialist in pt
taking Lithium:
1.eGFR is decreased by >4 ml/min
annually
2.Progressive rise in creatinine in 3 or
more serial test
3.Proteinuria
4.Haematuria
5.Symptoms of CRF(Anaemia,tiredness)
6.e-GFR <30 ml/min
60. Valproate:Monitoring
Indications Mania, hypomania, bipolar depression and
prophylaxis of bipolar affective disorder.
Note that sodium valproate is licensed only for epilepsy
and semi-sodium valproate only for acute mania
Pre-valproate
work up
FBC and LFTs. Baseline measure of weight
Prescribing Loading doses can be used and are generally well
tolerated. CR sodium valproate can be given once daily.
All other formulations must be administered at least
twice dailyPlasma levels can be used to assure adequate
dosing and treatment compliance. Blood should be taken
immediately before the next dose
Monitoring As a minimum, FBC and LFTs after 6 months
Weight (or BMI) should also be monitored
Stopping Reduce slowly over at least 1 month
61. Lab Monitoring:Carbamazepine
Test Frequency
Complete blood count (CBC) Before treatment and every 2 weeks
for the first 2 months of
treatment; thereafter, once every 3
months
Platelet count and reticulocyte count Before treatment and yearly
Serum electrolytes Before treatment and yearly
Electrocardiogram Before treatment and yearly
SGOT,SGPT,LDH Before treatment and every month
for the first 2 months of
treatment; thereafter, every 3
months
Pregnancy test for women of
childbearing age
Before treatment and as frequently
as monthly in noncompliant patients
62. Other Laboratory Tests
Test Major Psychiatric
Indications
Comments
Adrenocorticotropic
hormone (ACTH)
Organic workup Increased in steroid abuse; may
be increased in seizures,
Cushing's disease, and in
response to stress
Decreased in Addison's disease
Alanine
aminotransferase
(ALT)
Organic workup Increased in hepatitis, cirrhosis,
liver metastases
Decreased in pyridoxine
(vitamin B6) deficiency
Antinuclear
antibodies
Organic workup Found SLE and drug-induced
lupus (e.g., secondary to
phenothiazines, anticonvulsants)
63. Other Laboratory Tests
Test Major Psychiatric
Indications
Comments
Calcium (Ca) Organic workup
Mood disorders
Psychosis
Eating disorders
Increased in hyperparathyroidism,
delirium, depression, psychosis
Decreased in hypoparathyroidism,
long-term laxative use
Catecholamines
urinary and
plasma
Panic attacks
Anxiety disorders
Elevated in pheochromocytoma
Ceruloplasmin,
copper, serum
Organic workup Low in Wilson's disease
64. Other Laboratory Tests
Test Major Psychiatric
Indications
Comments
Cortisol Organic workup
Mood disorders
Excessive level may indicate Cushing's
disease associated with anxiety,
depression
Estrogen Mood disorder Decreased in menopausal depression
and premenstrual syndrome
Glutamyl
transaminase,
serum
Alcohol abuse
Organic workup
Increased in alcohol abuse, cirrhosis,
liver disease
Folate (folic
acid), serum
Vitamin B12,
serum
Alcohol abuse
Dementia
associated with dementia, delirium
alcohol dependence, use of
phenytoin, oral contraceptives
65. Other Laboratory Tests
Test Major Psychiatric
Indications
Comments
Holter monitor Panic disorder Evaluation of panic-disorder
patients with palpitations and
other cardiac symptoms
Nocturnal penile
tumescence
Erectile disorder Helpful in differentiation
between organic and functional
causes of impotence
Testosterone,
serum
Impotence
Hypoactive sexual
desire disorder
Increased in anabolic steroid
abuse
May be decreased in impotence
Decrease may be seen in
hypoactive sexual desire disorder
66. Take Home Message
No laboratory tests in psychiatry can confirm
or rule out diagnoses
Health screening should be done in all
psychiatric pt to exclude organicity
TFTs are used to rul out hypothyroidism which
can appear as MDD
DST:help confirm diagnostic impression of MDD
Always check for Metabolic syndrome patient
taking psychotropics
Lab tests should be arranged according to cause
in sexual dysfunction
67. Take Home Message
• Urine test is an important test for
substance abuser
• Be sure that pt is fit biochemically for
giving anaesthesia in ECT
• Drug level monitoring help in optimising
treatment & assure adherence
• Treat the patient,not the level
• ECG and haematological monitoring:
strongly recommended when parenteral
antipsychotics are given
68. Take Home Message
• Clozapine is associated with myocarditis
and cardiomyopathy
• ANC is mandatory blood monitoring for
clozapine
• Be aware about psychotropics induced
electrolytes imbalance
• RFTs,TFTs are most important Pre-
Lithium work-up
• Lithium toxicity is a medical emergency
often having fatal outcome
Notas do Editor
Table 2, current diagnostic criteria for the diagnosis of diabetes, is divided into five slides
On this slide, all four criteria are included:
A1C ≥6.5%
OR
Fasting plasma glucose (FPG) ≥126 mg/dL (7.0 mmol/L)
OR
2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during an OGTT
OR
A random plasma glucose ≥200 mg/dL (11.1 mmol/L), in patients with classic symptoms of hyperglycemia or hyperglycemic crisis
The subsequent four slides examine each of the four criteria in greater detail
The three primary criteria for testing for diabetes in asymptomatic adult individuals(Table 4) are summarized on two slides; this slide (Slide 1 of 2) includes:
Testing should be considered in all adults who are overweight (BMI ≥25 kg/m2) and have additional risk factors1
Testing should be considered in adults of any age with BMI ≥25 kg/m2 and one or more of the known risk factors listed on this slide1
There is compelling evidence that lower BMI cut-points suggest diabetes risk in some racial and ethnic groups1
In a large multiethnic cohort study, for an equivalent incidence rate of diabetes conferred by a BMI of 30 kg/m2 in whites, the BMI cutoff value was 24 kg/m2 in South Asians, 25 mg/m2 in Chinese persons, and 26 kg/m2 in African-Americans2
The three primary criteria for testing for diabetes in asymptomatic adult individuals(Table 4) are summarized on two slides; this slide (Slide 1 of 2) includes:
Testing should be considered in all adults who are overweight (BMI ≥25 kg/m2) and have additional risk factors1
Testing should be considered in adults of any age with BMI ≥25 kg/m2 and one or more of the known risk factors listed on this slide1
There is compelling evidence that lower BMI cut-points suggest diabetes risk in some racial and ethnic groups1
In a large multiethnic cohort study, for an equivalent incidence rate of diabetes conferred by a BMI of 30 kg/m2 in whites, the BMI cutoff value was 24 kg/m2 in South Asians, 25 mg/m2 in Chinese persons, and 26 kg/m2 in African-Americans2
The three primary criteria for testing for diabetes in asymptomatic adult individuals(Table 4) are summarized on two slides; this slide (Slide 2 of 2) includes:
In the absence of criteria (risk factors on previous slide), testing diabetes should begin at age 45 years
If results are normal, testing should be repeated at least at 3-year intervals, with consideration of more frequent testing depending on initial results and risk status
Age is a major risk factor for diabetes; therefore, testing of individuals (using A1C, FPG, or 2-hour OGTT) without other risk factors should begin no later than at age 45 years
The rationale for the 3-year interval is that false negatives will be repeated before substantial time elapses, and there is little likelihood that an individual will develop significant complications of diabetes within 3 years of a negative test result
Given the need for follow-up and discussion of abnormal results, testing should be conducted within the health care setting
Community screening outside a health care setting is not recommended because people with positive tests may not seek, or have access to, appropriate follow-up testing and care
Conversely, there may be failure to ensure appropriate repeat testing for individuals who test negative
Community screening may also be poorly targeted; i.e., it may fail to reach the groups most at risk and inappropriately test those at low risk (the worried well) or even those already diagnosed