Laboratory Procedures and Practices

Laboratory Requisition Form Components

The electronic laboratory requisition form in SimChart for the Medical Office includes various components that are critical for patient identification and testing. These components include:

• Certificate to Return to Work or School

• Disclosure Authorization

• Doctor's First Report

• General Procedure Consent

• Insurance Claim Tracer

• Medical Records Release

• Requisition Type (such as Laboratory)

• Patient Name

• Service Date

• Authorization Number (as needed)

• Date of Birth

• Insurance Company

• Ordering Physician

• Neurological Status Exam

Additional fields include:

• Diagnosis

• Patient Information

• Patient Records Access Request

• Patient Statement

• Diagnosis Codes

• Prior Authorization Request

• Referral

• Laboratory Requisition (includes school physical and vaccine authorization).

Laboratory Tests and Panels

Laboratory panels typically requested in medical settings often include:

• Electrolytes Panel

  • Sodium

  • Potassium

  • Chloride

  • Carbon Dioxide

• Basic Metabolic Panel (BMP)

  • BUN

  • Creatinine

  • Calcium

  • Glucose

• Comprehensive Metabolic Panel (CMP)

• Hepatic Function (Liver Panel)

  • Acute Hepatitis Panel, which includes:

  • Hepatitis A Antibody IGM

  • Hepatitis B Core Antibody IGM

  • Hepatitis B Surface Antigen

  • Hepatitis C Antibody

• TORCH Panel

  • Includes testing for Toxoplasmosis, Rubella, Cytomegalovirus, and Herpes Simplex Virus.

• Additional tests may include albumin and CMV antibodies.

Collection Procedures for Specimens

The responsibility of the medical assistant often includes the collection of various types of specimens with an emphasis on proper techniques and guidelines to ensure accuracy and reliability of test results:

Importance of Proper Specimen Collection

• The quality of laboratory results heavily relies on the adequacy of the specimen. Proper specimen collection ensures reliable indicators of the patient’s health status. Most common specimens include blood, urine, and swabs from wounds or mucous membranes, while less common specimens may include feces, gastric contents, cerebrospinal fluid (CSF), tissue samples, semen, and aspirates.

Patient Identification

• Verifying a patient's identity is critical before specimen collection. The standard procedure involves using a minimum of two patient identifiers to ensure accuracy; failure to do so could render laboratory results ineffective.

Specimen Containers

• The choice of specimen container (or collection tubes) is paramount. Blood samples, for instance, are drawn into vacuum tubes which come in various sizes and may contain preservatives or anticoagulants identified by color-coded stoppers. An incorrect choice of container can result in unacceptable specimens, necessitating recollection.

Sterility of Specimens

• For tests involving microorganisms, a sterile container is crucial to avoid contamination. If patients are instructed to collect specimens at home, they must be equipped with appropriate containers and clear instructions for collection.

Patient Instructions and Education

• Providing patients with comprehensive instructions for home collection, being cognizant of individual factors like hearing or language, and reinforcing the instructions through repetition, are crucial roles of the medical assistant. Patient education includes ensuring written directions accompany verbal instructions to bolster understanding and compliance.

Labeling of Specimens

• Each specimen container must be correctly labeled during collection to avoid errors. Acceptable labels include the patient's full name, identification number, date and time of collection, specimen type, and collector’s initials. Using a black waterproof marker is recommended, with pencils being unacceptable.

Preventing Contamination

• Medical assistants must exercise caution to prevent contamination during specimen collection. Checking expiration dates on all materials and adhering to Standard Precautions is essential, considering all specimens and fluids are potentially infectious.

Specimen Handling and Storage

Proper handling, processing, and storage of specimens according to the manufacturer’s guidelines is necessary to prevent alterations that could affect test results. Key practices include:

• Adhering to specific storage temperatures dictated by manufacturers for specific tests.

• Serum must be swiftly separated from blood cells post-clotting to avoid changes due to cell metabolism.

• For specimens requiring freezing, precise manufacturer guidelines should be followed to avoid degradation of chemical constituents.

Reference Laboratory Usage

When dealing with unfamiliar tests, the medical assistant should utilize the laboratory's specimen requirements manual or reference their website to resolve any uncertainties prior to specimen collection.

Specimens must not only be stored properly, but there are specific protocols for transport to ensure that they maintain their integrity. For example, if mailing specimens, packaging must be robust enough to prevent breakage and contamination, with proper labeling according to the test laboratory’s specifications.

Chain of Custody for Forensic Specimens

When dealing with specimens required for legal evidence, strict procedures for collection and handling must be applied to ensure their integrity. Chain of custody is a documented process ensuring that the specimen is collected, processed, and tested without tampering. This includes:

• Documentation should detail each individual's contact with the specimen, verifying its path from collection to reporting.

• Medical personnel may be required to testify regarding the specimens handled, necessitating rigor in adherence to these standards to maintain their validity within legal contexts.

Laboratory Mathematics and Measurement

Laboratory testing also involves precise values, units, and measurements crucial for specimen analysis:

Measuring Time

Time is an essential factor in patient care, impacting medication administration and test collection schedules. Laboratories commonly follow a 24-hour clock (military time) to minimize confusion. For instance:

• 1:00 a.m. = 0100 hours

• 3:00 a.m. = 0300 hours

• 5:00 a.m. = 0500 hours

• 1:00 p.m. = 1300 hours

• 12:00 a.m. = 2400 hours

Converting Temperatures

Laboratories must often convert temperature measurements between Fahrenheit and Celsius. For example, to convert 98.6°F to Celsius:

1. Subtract 32 from the Fahrenheit temperature.

2. Divide the result by 1.8.

• Example Transformation:
  $98.6°F - 32 = 66.6$
  $66.6 / 1.8 = 37°C$

To convert from Celsius to Fahrenheit, the steps are inverted:

1. Multiply Celsius temperature by 1.8.

2. Add 32 to that.

• Example:
  $100°C × 1.8 = 180$
  $180 + 32 = 212°F$

Units of Measurement Comparison

• Common laboratory measurements contrast with everyday life measurements, where the metric system is usually employed in labs:

  • Blood glucose in mmol/L as per SI units versus mg/dL in metric.

Measuring Liquid Volume

• Liquid specimens are often held in test tubes or measured using pipets. pipets may differ in design (e.g., transfer pipets) and accuracy for small volumes (micropipets).

Laboratory Equipment

Key laboratory instruments include:

• Microscopes: Used for viewing microscopic specimens. These need certified operators for their assessments as errors may lead to significant consequences.

• Centrifuges: Typically used to separate components of the specimen based on density.

• Incubators: Utilized to maintain constant conditions for biological specimens.

Each of these tools plays a crucial role in the functional operations of medical laboratories as medical assistants learn to effectively facilitate workflows within clinical settings.

Conclusion

The understanding and attentiveness to protocols and methodologies in the laboratory embody the essence of reliable and credible medical practice. From specimen collection to analysis, each step must be approached with diligence to ensure accurate patient results and care.