Urinalysis and Laboratory Results

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the normal specific gravity range of urine?

1000 - 1015

1015 - 1025 (correct)

1025 - 1030

1030 - 1045

Which condition can result in an odor of ammonia in urine?

Chronic renal failure

Diabetes ketoacidosis

Urinary tract infection (correct)

Obstructive jaundice

What indicates oliguria in terms of urine output?

< 500 mL/day (correct)

100-200 mL/day

20-100 mL/day

< 125 mL/day

What urinary abnormality is indicated by a colorless urine sample?

Chronic renal failure Signup and view all the answers

Which of the following urine aspects is indicative of pyuria?

Turbid Signup and view all the answers

When would urine likely present with a fruity odor?

Diabetes ketoacidosis Signup and view all the answers

What pH level is considered normal for urine?

5.0 - 6.5 Signup and view all the answers

What abnormal color in urine indicates the presence of bilirubin?

Yellowish brown Signup and view all the answers

What percentage of non-diseased individuals can have laboratory results outside the reference range?

5% Signup and view all the answers

What factor is NOT mentioned as contributing to the variability of laboratory test results?

Environmental factors Signup and view all the answers

In which situation is the interpretation of a laboratory test generally straightforward?

When monitoring a stable condition Signup and view all the answers

How can clinicians mitigate the risk of false interpretation of laboratory results?

By evaluating results alongside known biological variation Signup and view all the answers

What is a useful approach for establishing a diagnosis based on laboratory test results?

Using pattern recognition from multiple tests Signup and view all the answers

Which of the following statements is true regarding laboratory test results?

Variability can occur due to different methodologies used across laboratories. Signup and view all the answers

Why might laboratory test results differ among healthy individuals?

Reference ranges are not applicable to all individuals. Signup and view all the answers

Which technique is NOT typically associated with establishing a diagnosis based on laboratory test results?

Performing extensive imaging tests Signup and view all the answers

What is the purpose of using a blood culture bottle during sample collection?

To preserve the viability of microorganisms Signup and view all the answers

Which additive in a light blue top tube is essential for performing coagulation tests?

Sodium citrate Signup and view all the answers

What can result from inappropriate filling of sample tubes during collection?

Results may be incorrect Signup and view all the answers

Why should sample tubes be gently inverted after collection?

To mix the sample with anticoagulant Signup and view all the answers

What is required for proper labeling of sample tubes?

At least two identification points Signup and view all the answers

What type of tests can be performed with blood collected in a red top tube?

Chemistries and immunology Signup and view all the answers

What is the function of sodium fluoride in light grey top tubes?

Acts as an antiglycolytic agent Signup and view all the answers

For which tests is the use of EDTA essential?

Hematology e.g. CBC Signup and view all the answers

Which of the following locations can Point of Care Testing (POCT) be performed?

Physician office Signup and view all the answers

What is one major advantage of Point of Care Testing?

Reduction in turnaround time (TAT) Signup and view all the answers

Which of the following is a disadvantage of Point of Care Testing?

Increased risk of inaccuracies Signup and view all the answers

Laboratory test panels typically serve what purpose?

To determine a person’s general health status Signup and view all the answers

Which of the following statements about the ordering of laboratory tests is true?

No test should be ordered unless medically necessary. Signup and view all the answers

What benefit does Point of Care Testing provide in relation to sample registration?

Reduces time delays in sample registration Signup and view all the answers

What is a typical feature of standardized laboratory test panels?

They have been standardized internationally. Signup and view all the answers

What defines gross hematuria?

Blood can be seen by the naked eye, making urine appear pink, brown, or red. Signup and view all the answers

Which of the following is NOT considered a location for Point of Care Testing?

Insurance Company Signup and view all the answers

How is microscopic hematuria defined?

Detected by seeing more than 5 red blood cells per high powered field on a specimen. Signup and view all the answers

Which of the following is likely to cause pyuria?

Upper and lower urinary tract infections. Signup and view all the answers

What is the importance of renal tubular epithelial cells in a urine sample?

Their increase can indicate nephrotic syndrome or tubular degeneration. Signup and view all the answers

Which types of cells can lead to contamination in urine samples?

Squamous epithelial cells. Signup and view all the answers

What are urinary casts primarily composed of?

Mucoprotein formed in specific kidney structures. Signup and view all the answers

What does the presence of crystals in urine indicate?

Possible presence of stones or metabolic imbalances. Signup and view all the answers

Which type of cast is primarily formed from Tamm-Horsfall proteins?

Hyaline casts. Signup and view all the answers

What information does the Basic Metabolic Panel (BMP) primarily provide?

Kidney and respiratory health, electrolyte balance, and blood glucose level. Signup and view all the answers

Which panel is specifically used to assess cardiovascular disease risk?

Lipid Panel Signup and view all the answers

What is the main purpose of the Electrolyte Panel?

To detect issues with fluid and electrolyte balance. Signup and view all the answers

Which panel contains tests specifically for liver function?

Hepatic Panel Signup and view all the answers

What type of tests does the Renal Panel include?

Tests specifically to evaluate kidney functions. Signup and view all the answers

What is the role of electrolytes in the body?

To assist in the movement of nutrients and waste in cells. Signup and view all the answers

Which laboratory test panel may include evaluations for thyroid disorders?

Thyroid Panel Signup and view all the answers

Which panel typically contains the most tests?

Comprehensive Metabolic Panel Signup and view all the answers

Signup and view all the answers

Study Notes

Medical Laboratory Testing Basic Principles

70% of medical decisions rely on lab test results.
Future physicians need to understand lab test ordering for patient care and cost-effectiveness.
Proper sample collection, handling, and transportation are crucial for accurate results.
Communication with lab specialists is essential for better patient care.

Laboratory Testing Cycle (Laboratory Work Flow)

The lab testing cycle comprises three phases: pre-analytical, analytical, and post-analytical.
Pre-analytical phase errors are the most frequent cause of lab test errors (62-76%).
Pre-examination phase includes test selection, sample collection, and transport.
Examination phase involves laboratory analysis.
Post-examination phase comprises report creation, transport, and result interpretation.

The Three Phases of Laboratory Testing

Pre-analytical Phase: Test ordering, specimen collection, transport, and processing.
Analytical Phase: Testing.
Post-analytical Phase: Results transmission, interpretation, follow-up, and re-testing.

Most Inaccurate Results

Most inaccurate results stem from errors in the pre-analytical phase.

Percentage of Laboratory Errors Reported in Each Phase of Laboratory Testing Cycle

Pre-analytic: 62-76%
Analytic: 6-15%
Post-analytic: 18-30%

From the Patient to the Lab - Common Errors

Incorrect test ordering.
Request form errors.
Incorrect patient identification.
Incorrect patient preparation (fasting, diet).
Inaccurate sample timing.
Sample poorly/incorrectly taken.
Wrong type of sample.
Incorrect containers (under-filling/over-filling).
No labeling/mislabeling of samples.
Incorrect storage/transport (temperature/delay).
Loss, breakage, and leakage.

Laboratory Tests Turnaround Time (TAT)

TAT is a critical measure of lab performance.
Different definitions of TAT exist among clinicians and lab personnel.
Lab personnel define TAT as the time from sample receipt to report generation.
Clinicians define TAT as the time from test requisition to receipt of the report.
TAT should be clearly defined in each institution.

Laboratory Tests Turnaround Time (TAT) - Reasons for TAT Importance

Supports patient-centered care.
Important for accurately evaluating lab performance.
Contributes to patient and physician satisfaction.
Delays are a major source of complaints from lab users.
TAT is a critical lab performance metric.

Laboratory Test Ordering

Crucial for accurate patient care.
Key considerations in test ordering include the rationale for testing, appropriate test selection, and accurate request form completion.

Indications for Ordering Laboratory Tests

Confirming a diagnosis.
Helping in differential diagnosis.
Evaluating prognosis.
Monitoring therapy.
Screening for a disease.

Proper Completion of Laboratory Request Form

Request forms must contain: patient's full name, date of birth, gender, medical record number, date of request, clinical diagnosis, ordered tests, and physician's signature.

Sample Collection

Quality and safe patient care relies on proper patient identification.
Correct timing and handling of samples are vital to accurate results.
Proper procedures for sample collection are important.
The use of various colored sample tubes corresponds to specific tests.
Correct sample tubes are essential for the proper test.
Proper labeling and pairing of samples with requisition forms is essential.

Proper Patient Identification

Proper patient identification is crucial to international lab safety.
Patient identifiers used include full name, date of birth (DOB), and medical record number.

Proper Sample Collection - General Considerations

Follow patient instructions (fasting for certain tests).
Use appropriate sampling times for specific tests (e.g., cortisol).
Collect samples from suitable veins.
Observe infection control procedures (short tourniquet time).
Use the correct tube for the test.
The tube must be labeled in front of the patient by the person who collected the sample.

Basic Phlebotomy Supplies

Requisition
Gloves
Tourniquet
Needle/Syringe
Tubes
Alcohol
Cotton or Gauze
Bandage or Tape
Proper labeling

Proper Sample Collection - Practices to Follow

Sample collection, collection and label samples for one patient at a time.
Proper tubes correctly.
Maintain proper sample mixing procedure (invert 5-8 times, do not shake.)

Proper Sample Labeling

Sample tubes should be labeled immediately after collection with bar codes or manually using two patient identifiers.
Identifiers include full name, date of birth, or medical record number.

Proper Sample Transportation

Place samples in a biohazard transport box.
Transport the sample immediately to the lab along with the request form.
Do not carry samples by hand or in pockets.

Laboratory Sample Delivery

The lab verifies that tubes are firmly covered, labels are complete and match requests, sample volume is appropriate, sample quality is suitable, and sample type is correct for requested tests.

Sample Rejection Criteria

Unlabeled or incompletely labeled samples.
Mismatched labeling and requisition.
Insufficient sample volume.
Unsuitable sample (hemolyzed specimen).
Insufficient volume of preservative.
Prolonged transport times.
Improper collection techniques

Laboratory Test Results Interpretation

Laboratory results must be interpreted within the context of a person's general health status as compared to reference values.
Reference intervals may vary based on age, sex, race, pregnancy, or the test methodology used.
Variability in test results is expected and should be considered by the clinician.
Sources of variability include patient posture, diet, medications, and others.

Reference Values

Reference intervals are used to distinguish between health and disease.
Types of reference values include reference intervals (ranges), decision cut-offs (positive or negative), and therapeutic ranges.

Variability of Laboratory Test Results

Different laboratories may generate different results due to the methods and techniques used.
Biological, pre-analytical, analytical, and post-analytical factors can contribute to test result variability in repeated measurements within and between individuals

Variables Affecting Test Results

Patient variables (diet, body mass, age, medications, gender, smoking, exercise, race, dehydration)
Specimen collection variables (posture, diurnal variations, time of collection, fasting status, tourniquet, presence of IVs, capillary vs venous)
Specimen handling variables (hemolysis, lipemia, centrifugation, processing time, temperature, sunlight, evaporation, aliquoting, labeling, transport conditions, order of draw)

How to Establish Diagnosis Based on Laboratory Test Results

For some tests, the interpretation of lab results is straightforward (e.g., monitoring anticoagulant therapy).
In other cases, a renal panel may be used for diagnosis, screening or monitoring.
Panel test results can suggest a pattern of conditions.
Hypothesis must be established by correlating the lab results with clinical evaluation.

Medical Algorithms

Medical algorithms are helpful in the sequential process of testing needed to rule out various possible conditions.
Example: an algorithm for anemia evaluation based on Hemoglobin concentration, PCV, RBCs, MCV, and others

Critical Results

Critical values are test results that significantly deviate from the normal reference range and may pose a life-threatening risk.
Health care providers must act immediately upon receiving critical values.
Appropriate communication channels for critical values should be established.
Example critical values include glucose, hemoglobin, platelets, and INR.

Complete Blood Count (CBC) Interpretation/Anemia

CBC is a routine blood test to measure different components and to determine the possibility of anemia
Various medical parameters of a CBC are used to determine anemia such as hemoglobin, haematocrit, RBCs count, RBC Indices, WBCs total count, WBCs different count, Platelet count

Blood Groups

Blood types are categorized as A, B, AB and O based on the presence or absence of A and B antigens on red blood cells (RBCs).

Blood Group System and Compatibility

Blood compatibility is crucial for safe blood transfusions.
Blood type O is the universal donor (compatible with all types), and type AB is the universal recipient (accepts blood from all types).

Basic Blood Components Processing

Whole blood is processed to separate components (packed RBCs, platelet rich plasma, fresh frozen plasma, cryoprecipitate, etc.).
Soft and Heavy spins are used in the processing for various components

Rationale Use of Blood Components

Different blood components have varying storage requirements and shelf lives. - Red cells and plasma have different storage times.

Blood Components Modifications

Modifications like leucoreduction, washing, irradiation, and freezing are applied to improve blood safety and efficacy.

Blood Transfusion Reactions

Adverse events or complications related to blood transfusions.
Immunological reactions (both acute and delayed hemolytic reactions, febrile nonhemolytic reactions, allergic reactions, transfusion-related acute lung injury (TRALI), transfusion-associated graft-versus-host disease).
Non-immunologic reactions (bacterial contamination, circulatory overload, physical/chemical hemolysis).

Transfusion Reactions Workup

Steps to follow when a transfusion reaction is suspected.
First, stop the transfusion and perform a clerical check.
Draw a post-transfusion sample for tests (ABO/Rh testing, hemoglobinemia, others).
Further testing (if necessary) include haptoglobin, LDH, bilirubin, and urine HGB for diagnosis

Urinalysis

Urinalysis includes physical, chemical, and microscopic examinations to assess urine constituents.
The technique requires proper sample handling to ensure accurate results.

Urinalysis - Physical Examination

Volume (normal range: 800-2000 mL/day; abnormal values can indicate kidney disease).
Odor (normal: urineferous; abnormal: fruity, ammonia).
Color (normal: pale yellow; abnormal: colorless, orange, red, black).
Aspect (normal: clear; abnormal: turbid).
Specific gravity (normal range: 1015-1025): abnormal values can indicate kidney issues, dehydration, or other metabolic disorders)
pH (normal range: 5-6.5): a change in pH may indicate an issue in the urinary tract

Urinalysis- Chemical Examination

Chemical examination assesses urine using dipsticks with color-coded results
Dipsticks indicate the presence of substances like glucose (diabetes mellitus), ketones (diabetes or starvation, bilirubin (liver disease), blood (urine infection, tumors, stones), protein (kidney disease), urobilinogen (liver issues), nitrite (urinary tract infection), and others

Urinalysis- Microscopic Examination

Microscopic examination of urine sediment identifies cells (red blood cells (RBCs), white blood cells (WBCs), epithelial cells, casts), crystals (oxalates, urates, phosphates), and organisms.
Example: microscopic hematuria (RBCs greater than 5 per high power field) could indicate glomerular damage, tumors, urinary tract stones or infection.

Point of Care Testing (POCT)

POCT (point-of-care testing) is a testing method that can be done at or near the patient's bedside.
POCT is generally performed outside of a central laboratory and includes tests like urine dipsticks, pregnancy tests, and glucose meters.
Advantages include reduced turnaround times, minimized delays, and direct results that facilitate better patient care decisions.
Some disadvantages include potential errors, required administrative efforts (training, certification of staff).

Laboratory Test Panels

Test panels group related tests performed routinely to assess a person's overall health status.
Examples of panels include Basic Metabolic Panel (BMP), Comprehensive Metabolic Panel (CMP), Electrolyte Panel, Lipid Panel, Hepatic Panel (liver function tests), Renal Panel (kidney function tests), and Thyroid Panel (thyroid function tests)

Infection Control

Infection control refers to a variety of practices and procedures for reducing the risk of infection spreading, especially in healthcare facilities.
A hospital acquired infection is an infection contracted in a healthcare setting that wasn't incubating when the patient was admitted

Chain of Infection

The chain consists of an infectious agent (pathogen), reservoir (where the pathogen lives), portal of exit, mode of transmission, portal of entry, and susceptible host (person who gets infected)

Standard Precautions

Standard Precautions are a set of infection control practices in healthcare settings to prevent the spread of infectious diseases, especially through direct contact (e.g. via hands of healthcare workers).
- Includes hand hygiene, safe injection practices, appropriate use of personal protective equipment and appropriate waste disposal.

Personal Protective Equipment (PPE)

PPE (Personal Protective Equipment) is specialized clothing or equipment specifically to protect individuals against infectious microorganisms.

Antibiotic Stewardship

Antibiotic stewardship is a systematic approach to wisely using antimicrobial agents so better treatment outcomes for patients, and reducing the development of antibiotic resistance.
Physicians must obtain appropriate cultures in suspected infections and promptly use antibiotic therapy
Overuse of antibiotics results in adverse effects & increased likelihood of multidrug resistant bacteria (e.g. super infections with Clostridium difficile).
Aims to prevent antibiotic resistant bacteria.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz focuses on key concepts related to urinalysis and laboratory results interpretation. Questions cover specific gravity, urine odors, pH levels, and factors influencing test outcomes. Test your knowledge on how urinary abnormalities reflect health conditions.