ABPM Occupational Medicine flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

Sensitivity definition

Proportion of people with disease who test positive: TP/(TP+FN). A highly sensitive test rarely misses disease, so a negative result helps rule out the condition.

Specificity definition

Proportion of people without disease who test negative: TN/(TN+FP). A highly specific test rarely produces false positives, so a positive result helps confirm the condition.

Positive predictive value

Proportion of positive test results that are true positives: TP/(TP+FP). PPV rises as disease prevalence in the tested population rises.

Negative predictive value

Proportion of negative test results that are true negatives: TN/(TN+FN). NPV is highest when the disease prevalence in the population is low.

Number needed to treat

Reciprocal of the absolute risk reduction: NNT = 1/ARR. It estimates how many patients must be treated for one additional favorable outcome.

Relative risk

Ratio of incidence in the exposed group to incidence in the unexposed group. It quantifies association strength but does not by itself show absolute benefit or harm.

Lead-time bias

Apparent survival gain from screening because diagnosis occurs earlier, even when the time of death is unchanged. It falsely inflates survival statistics without altering mortality.

Length bias

Screening preferentially detects slowly progressive disease with long preclinical phases, making screened cases appear to survive longer than clinically detected cases.

Herd immunity threshold

Approximately 1 − 1/R0. The fraction of a population that must be immune to interrupt sustained transmission of an infectious agent.

Secondary prevention

Detection of disease in its preclinical or early stage to allow earlier treatment, such as screening mammography, colonoscopy, or blood pressure screening.

Case-fatality rate

Number of deaths from a disease divided by number of diagnosed cases over a defined period. It reflects severity rather than overall population burden.

Crude versus adjusted rates

Crude rates reflect actual population experience; adjusted rates remove the effect of age or other confounders so groups with different structures can be compared fairly.

Cross-sectional study

Measures exposure and outcome simultaneously in a population sample. It estimates prevalence and association but cannot establish temporal sequence or causality.

Cohort study measure

Prospective or retrospective follow-up of exposed and unexposed groups yields incidence and relative risk, and can establish temporal order between exposure and outcome.

Case-control study measure

Compares prior exposure among people with and without disease; the odds ratio is the measure of association, efficient for rare outcomes.

OSHA permissible exposure limit

Enforceable regulatory limit, usually an 8-hour time-weighted average. The action level, often half the PEL, triggers monitoring and medical surveillance obligations.

OSHA noise action level

85 dBA as an 8-hour TWA. At or above it, a hearing conservation program with audiometry, hearing protection, and training is required.

Standard threshold shift

Average hearing loss of 10 dB or more at 2000, 3000, and 4000 Hz in either ear compared with baseline audiogram, triggering follow-up and notification.

Asbestosis

Diffuse interstitial pulmonary fibrosis from inhaled asbestos fibers, typically after high cumulative exposure and a latency of many years; it is distinct from asbestos-related malignancy.

Asbestos and smoking synergy

Smoking and asbestos exposure multiply lung cancer risk far beyond additive effects, while smoking does not increase mesothelioma risk attributable to asbestos.

Silicosis and tuberculosis

Respirable crystalline silica causes nodular fibrosis, and silicosis substantially increases susceptibility to tuberculosis, a classic occupational comorbidity.

Lead poisoning findings

Anemia with basophilic stippling, abdominal pain, peripheral neuropathy, hypertension, and renal injury. Blood lead levels guide medical removal from exposure.

Benzene health effects

Chronic exposure suppresses bone marrow, causing aplastic anemia and leukopenia, and is established as a cause of acute myeloid leukemia.

Carbon monoxide mechanism

CO binds hemoglobin with roughly 200–250 times the affinity of oxygen, shifting the dissociation curve left and impairing tissue oxygen delivery.

Occupational asthma pattern

Airflow obstruction with symptoms improving on days away from work. Serial peak flow records at and away from work support the diagnosis.

PEL versus TLV

PELs are enforceable OSHA limits; TLVs are non-regulatory recommended values from ACGIH, and NIOSH RELs are federal research recommendations.

Medical surveillance purpose

Periodic health testing of workers with defined exposures to detect early adverse effects, verify control effectiveness, and guide removal or restriction from exposure.

Occupational history elements

Job title, industry, specific tasks, duration, chemical and physical agents, protective equipment use, and symptom timing relative to work shifts.

Confined space hazards

Oxygen deficiency or enrichment, flammable gases, and toxic atmospheres. Entry requires atmospheric testing, ventilation, attendant, and rescue plan before entry.

Heat illness prevention

Acclimatization, water, rest, shade, and monitoring. Heat stroke is a medical emergency requiring rapid cooling; heat exhaustion responds to rest and rehydration.

Fitness for duty evaluation

Assessment of whether a worker can safely perform essential job functions, considering physical demands, exposures, and medical conditions, with accommodations where appropriate.