CLS-301 - Specimen Management

What does specimen management include?

test orders/requisitions, specimen collection, labeling, handling, transport, and processing

Why does specimen management matter?

quality specimens = quality results

What are the 3 phases of clinical lab testing?

pre-analytical, analytical, post-analytical

What is included in the pre-analytical phase?

test orders/requisitions, specimen collection, labeling, handling, transport, and processing

Laboratory Test Requistions

generated from the physician’s order (verbal, written, or electronic) - includes patient name, DOB, MRN, physician’s name, date/time specimen is to be collected, name of tests ordered, test status, space for initials of phlebotomist

What are the test statuses?

timed, fasting, STAT, location (if in-patient)

Sterile Body fluids other than blood

cerebral spinal fluid, pericardial fluid, pleural fluid, peritoneal fluid, synovial fluid

Other types of specimen collection

urine, stool, sputum, throat, and nasopharyngeal

Cerebral Spinal Fluid (CSF)

always STAT specimen, collected by lumbar puncture between L3/L4 vertebrae by MD into 4 sterile tubes (tube 1: non routine studies, tube 2: immunology/chemistry, tube 3: microbiology, tube 4: hematology/cytology

Pericardial Fluid

thin sac filled with fluid surrounding the heart - needle is inserted into chest between the ribs into the pericardium to withdraw small amount of fluid

Pericardial effusion

abnormal build-up of fluid that develops between the pericardium and the heart

pleural fluid

fluid that surrounds the lungs - excessive amounts can impair breathing by limiting the expansion of the lungs (pleural effusion)

peritoneal fluid

area between the abdominal wall and the organs housed in the abdomen that is filled with small amount of fluid - build up of fluid can occur when there is disease or infection (ascites)

Paracentesis

process of obtaining fluid from the peritoneal space (when collecting amniotic fluid always protect from light as they check bilirubin levels)

Synovial fluid

fluid present between the joint spaces - reduces friction and acts as a shock absorber - used to determine reasons for inflammation (Monosodium Urate (MSU) crystals, Calcium Pyrophosphate Dihydrate (CPPD) crystals)

Urine specimens

most commonly analyzed non-blood specimen, routine analysis - can indicate bladder, kidney, endocrine, and metabolic issues - testing can also include microbiology culture for UTI, pregnancy testing, toxicology, sexually transmitted infections/diseases

Random urine collection

random

First morning specimen urine collection

before drinking any fluids, urine is the most concentrated

Fasting urine collection

preferred for glucose testing

Timed/24hr urine collection

measure of urine output, should be kept refrigerated

Clean catch/Midstream urine collection

collected after cleansing the external genitalia, preferred for microbiology culture

Stool Specimen

ova and parasite exam, wet mounts, permanent smears, meconium (neonates first bowel movement)

Fixatives used for Wet Mounts

5/10% formalin, Merthiolate Iodine Formalin (MIF), Sodium Acetate-Acetic Acid Formalin (SAF), Total-FixFi

Fixatives used for Permanent Smears

mercury bases polyvinyl alcohol (Hg-PVA), Zinc/Copper based PVA, Schaudinn’s Fluid

Sputum Collection

patient must produce sputum (not spit) from deep within the respiratory cavity - tests include culture and stain for infectious disease - swabs are rejected

Induced Sputum

may be collected by respiratory therapists

Throat swabs

can be used for culture - diagnosis of strep throat

Nasopharyngeal swabs

used for diagnosing respiratory infections including COVID, influenza, pneumonia, whooping cough

Glucose Tolerance Testing

determines body’s ability to metabolize sugar by administering standard does of glucose - blood and urine glucose are tested at regular intervals (Fasting blood glucose tested first - if normal tolerance test may proceed)

Oral Glucose Tolerance Test (OGTT)

patient fast overnight, fasting level is collected first, 75g glucose solution given to patient (must be swallowed within 5 min), 2-hour post prandial (blood drawn 2 hrs later)

Normal glucose level at 2-hour post-prandial

less than 140mg/dL

Pre-diabetic glucose level after 2-hour post prandial

between 140-200 mg/dL - suggests impaired glucose metabolism

Glucose level that suggests diabetes mellitus after 2-hour post prandial

greater than 200 mg/dL

What is the OGTT used for?

used to screen pregnant women for gestational diabetes between 24 and 48 weeks of pregnancy - to diagnose diabetes when suspected despite normal fasting blood glucose

Glycosylated Hemoglobin (HbA1C)

reflects the mean level of blood glucose over the past 3 months (RBCs have circulating lifespans of 120 days/ 3 months) - normal level is 4.5-5.7%

Glucose molecules attach to hemeoglobin

rate of attachment is directly proportional to plasma glucose concentration

Advantages of glycosylated Hemoglobin (HbA1C) test

better index of overall glycemic exposure and risk for long term complications, less biological and pre-analytical variability than glucose, no need for fasting/timed samples, relatively unaffected by stress or illness

Forensic testing

specimens used in legal cases - labs are legally accountable for documentation of evidence from time of collection to time of disposal (chain of custody) T

Toxicology

study of poisons and includes their detection, actions on the body, and possible treatment - includes drugs-of-abuse, blood alcohol testing, athletic testing, and neonatial testing

Role of healthcare workers (HCW) in forensics

initiates chain of custody, prevent specimen alteration, ensure that specimen is tamper-proof (temp within 4 min, specific gravity measure to detect dilution), custody and control form

Performance-enhancing substances

testing used in competitive sports, usually urine sample because drugs and drug metabolites are more concentrated in the urine than in the blood

Therapeutic Drug Monitoring (TDM)

timed specimen - peak level is highest concentration an analyte reaches in a patient and the trough level is the lowest

Specimen Labeling

must include two patient identifiers, date/time of specimen collection, phlebotomist’s initials/ID - CLSI provides guidelines on format, placement, size, and orientation

Specimen Transport

specimens should be enclosed in leak-proof plastic bag with proper biohazard labeling and accompanying paperwork should be protected from leaks

Specimens sensitive to cold

cold agglutinins are antibodies that attach to RBCs when temp drops below 37 deg C, cryoglobulins are abnormal serum proteins that precipitate when temp drops below 37 deg C - prewarm tubes and keep warm during transport

Specimens that require transport on ice/cold pack

blood gases, ammonia, free/ionized calcium, lactic acid, renin

Photosensitive specimens

affected by exposure to UV light - bilirubin, porphyrins (essential for hemoglobin function) - use amber colored collection tubes

Accession Number

unique specimen ID assigned to each specimen once it has been inspected and has met the applicable criteria

Specimen Processing

note receive time, accept specimens, assign accession number, work with STAT specimens first, note and separate specimens requiring centrifugation, properly label aliquots and send them to specific bench for analysis

Pre-Analytical Variables

wrong tests ordered, incorrect patient identification, poor patient prep (no fasting, interfering medications), suboptimal specimen collection, wrong specimen collected for test ordered, inaccuarate timing of sample collection, incorrect containers used for transport, under/over filling, incorrect order of draw, mislabeled/unlabeled

Pre-Analytical Errors

occur prior to testing or analysis - may cause erroneous or misleading results - can be from expired reagents, media, supplies, or phlebotomy collection

Hemolysis

releases of hemoglobin into fluid portion of blood as a results of breaking apart of RBCs - may occur through mechanical means or because of poor phlebotomy technique

Hemoconcentration

increased concentration of larger molecules and formed elements in the blood

Lipemia

cloudy serum or plasma due to excessive lipids in specimen - can falsely elevate liver function test values - can indicate that patients did not fast before specimen collection

Icteric

plasma/serum have yellow-greenish appearance - elevated bilirubin levels associated with jaundice, falsely elevated cholesterol - most likely due to patient’s disease state

Processing Errors

delayed separation, after 18-24 hrs loss of electrolytes, after 72 hours visible hemolysis occurs