Section 3.2: Specimen Collection & Fluid Intake/Output (I&O)

Specimen Collection & Fluid Intake/Output (I&O)

Fluid balance is a critical indicator of renal, cardiovascular, and metabolic health, particularly in the elderly population. Under Iowa Administrative Code (IAC) 441 Chapter 81, long-term care facilities must monitor and document nutritional and hydration status to prevent complications such as dehydration, fluid overload, and electrolyte imbalances. Certified Nursing Assistants (CNAs) are responsible for the meticulous measurement and recording of Intake and Output (I&O), as well as the safe collection of diagnostic specimens.

Measuring and Calculating Fluid Intake

Fluid intake includes all fluids the resident consumes by mouth, as well as nutritional fluids received via enteral (nasogastric or gastrostomy) tubes or intravenous routes (though IV fluids are documented by the nurse).

• The Room Temperature Rule: Any food item that is liquid at room temperature must be measured and recorded as fluid intake. This includes:
  • Water, juice, milk, coffee, tea, and soft drinks.
  • Soups and broths.
  • Gelatin (Jell-O), popsicles, ice cream, sherbet, and custard.
  • Exclusions: Pudding, applesauce, and yogurt are generally not counted as liquid intake in standard clinical settings because they do not melt to a liquid state at room temperature, though you should always check your facility’s specific policy.
• Mathematical Conversion: In healthcare, fluid volume is documented using milliliters (mL) or cubic centimeters (cc), which are equivalent (1 mL = 1 cc). Since dietary trays and cups are often marked in ounces (oz), CNAs must perform accurate conversions using the standard multiplier:
  • 1 ounce (oz) = 30 milliliters (mL)

Intake Calculation Example

A resident is served the following breakfast tray:

• 1 carton of milk (8 oz) — Resident drinks the entire carton.
• 1 cup of coffee (6 oz) — Resident drinks half the cup (3 oz).
• 1 bowl of oatmeal — Resident eats all of it (not counted; solid food).
• 1 container of gelatin (4 oz) — Resident eats the entire container.
• 1 glass of cranberry juice (4 oz) — Resident drinks 75% of it (3 oz).

To calculate the total intake in mL:

1. Milk: 8 oz * 30 mL/oz = 240 mL
2. Coffee: 3 oz * 30 mL/oz = 90 mL
3. Gelatin: 4 oz * 30 mL/oz = 120 mL
4. Cranberry Juice: 3 oz * 30 mL/oz = 90 mL
5. Total Intake: 240 + 90 + 120 + 90 = 540 mL

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Measuring Fluid Output

Fluid output consists of all fluids that exit the body. This is crucial for evaluating renal function and identifying fluid retention:

• Components of Output: Urine, liquid feces, emesis (vomit), wound drainage, and nasogastric suction drainage. Normal solid stool is documented by count/character, not in mL.
• Measurement Protocol: Never estimate fluid output. Pour the fluid (e.g., from a bedpan, urinal, or urinary drainage bag) into a graduated cylinder (graduate). Place the graduate on a flat, stable surface (such as a paper-towel-lined counter) at eye level to read the measurement. Reading it while holding it in the air or on an uneven surface leads to significant errors. Clean and disinfect the graduate according to facility protocol.

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Clinical Signs of Fluid Imbalance

CNAs must observe residents for signs of fluid imbalance and report them immediately to the nurse:

• Dehydration (Fluid Volume Deficit): Symptoms include dry mucous membranes (dry mouth/lips), cracked tongue, dark or concentrated urine, low urine output, sunken eyes, rapid heart rate, low blood pressure, confusion, and poor skin turgor (though skin turgor is less reliable in elderly residents due to loss of elasticity).
• Fluid Overload (Fluid Volume Excess): Occurs when the body retains abnormal amounts of fluid. Signs include edema (swelling, particularly in the feet, ankles, and hands), sudden weight gain (e.g., 2 pounds or more in 24 hours), shortness of breath (dyspnea), coughing, increased blood pressure, and jugular vein distension.

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Specimen Collection Protocols

Diagnostic specimens must be collected using aseptic techniques to prevent contamination and ensure accurate laboratory analysis.

1. Urine Specimens

• Routine Urinalysis: Collected during normal voiding. Ask the resident to urinate into a clean bedpan, urinal, or specimen pan ('hat') placed in the toilet. Ensure they do not put toilet paper or feces into the specimen.
• Mid-Stream Clean-Catch: Used to detect urinary tract infections (UTIs). Clean the perineal area thoroughly with antiseptic wipes (front-to-back for females; circular motion from the meatus outward for males). Ask the resident to begin urinating into the toilet or bedpan, then position the sterile specimen cup into the stream to collect the sample mid-stream without touching the inside of the cup or the resident's skin. Remove the cup before the stream stops.
• 24-Hour Urine Collection: Used to evaluate kidney function over a full day. State the start time (e.g., 07:00 AM). Ask the resident to void immediately. Discard this first void so the collection begins with an empty bladder. Collect all urine voided over the next 24 hours. The container must be kept on ice or refrigerated. Critical Rule: If any urine is discarded by mistake, or if the resident defecates into the container, the entire test is ruined. You must notify the nurse, discard all collected urine, and restart the 24-hour clock the next morning.

2. Stool Specimens

Stool specimens are collected to test for blood (occult blood), parasites, or pathogens (such as C. difficile). Have the resident defecate into a clean specimen pan. The stool must not be contaminated with urine or toilet paper. Use a sterile tongue blade to collect samples from two different sections of the stool. Place the samples in the specimen container, secure the lid, and dispose of the tongue blades in the trash.

3. Sputum Specimens

Sputum is mucus coughed up from the lungs (bronchial secretions), not saliva. It is tested for respiratory infections like pneumonia or tuberculosis. Collect the specimen first thing in the morning when secretions have accumulated overnight. Have the resident rinse their mouth with water first to remove food particles and saliva (do not use mouthwash, as it can kill the pathogens being tested). Ask the resident to take three deep breaths and cough deeply from the chest to expectorate directly into the sterile specimen container.

Labelling and Infection Control Rules

To prevent diagnostic errors, CNAs must follow strict labelling and transport protocols:

• Label at the Bedside: Always write the resident’s full name, date of birth, date, time of collection, and your initials on the label in the resident’s presence immediately after collection. Never label a container before entering the room, and never leave the room with an unlabeled specimen.
• Biohazard Transport: Place the labelled specimen container into a plastic biohazard bag. Remove your gloves, wash your hands, and transport the specimen immediately to the designated lab area or refrigerator.