14.2 Waived Urinalysis Procedures and Specimen Handling

CMLA III.9.B tests whether you can prepare, store, dispose of, and properly transport UA specimens and perform urinalysis tests within the laboratory assistant’s scope. Scope is unmodified waived reagent-strip UA (visual or a waived reader) plus the handling that keeps the result valid. Slide preparation is started here and finished in Section 14.3. Qualitative urine human chorionic gonadotropin (hCG) is commonly waived; it is an immunoassay (Chapter 12), not a dipstick pad—follow that cassette’s IFU and do not treat a pregnancy device as a Chemstrip.

Quick Answer: Mix, label, and test unpreserved UA promptly (commonly within 2 hours) or refrigerate. Bring cold specimens toward room temperature before dipping. Read each pad at the IFU time. Prevent runover. Do not report a strip as culture. Tablet confirmations (Ictotest, SSA, historically Clinitest) follow the current IFU; many laboratories have retired Clinitest. Dispose of urine as a biohazard under Standard Precautions.

Handle the specimen before you dip

1. Identity. Two identifiers match the order (CLSI PRE01). An unlabeled bathroom cup is a rejection, not a dip (Chapter 9).
2. Suitability. Match the cup to the test. A boric-acid C&S tube is often the wrong aliquot for reagent strips because the preservative can distort pH and other pads. Fecal contamination, leakage, insufficient volume, and delayed unrefrigerated urine are rejections.
3. Mix. Cells and casts settle. Invert gently. Do not shake a foam that you then call protein.
4. Temperature. If the cup was refrigerated, let it warm toward room temperature per SOP before chemical testing. Cold urine can dull some pad reactions and dump amorphous crystals into the sediment. Warming to dissolve amorphous urates or phosphates is an SOP step, not a reason to incubate the cup on a heater block you invented.
5. Timing. Unpreserved routine UA: examine promptly, commonly within 2 hours, or refrigerate (typically 2–8°C). Delay grows bacteria (false nitrite, false cloudiness), consumes glucose, lyses cells and casts, fades bilirubin and urobilinogen, and raises pH as urea becomes ammonia.
6. Transport. Leak-proof lid, biohazard bag, upright, labeled, no delay on a warm counter. Send-outs follow CLSI PRE04/PRE05 and the receiving laboratory’s catalog. Do not ship an open cup in a staff coat pocket.
7. Dispose. Treat urine as potentially infectious. Empty per SOP into the designated sink or waste, then discard the cup in biohazard waste. Used strips are wet with urine—biohazard, not office trash. Do not pour leftover UA down a public restroom because it is “only urine,” and do not store leftover cups in the staff refrigerator beside lunch.

Waived chemical UA: the pads

A typical 10-parameter reagent strip (follow the brand in your hand) includes the pads below. Visual reading uses the chart on the bottle; a waived automated reader times and reads for you if that system is cleared as waived and you use it unmodified.

Physical (macroscopic) observations still count. A red, blood-pad-negative specimen may be beets, porphyrins, or dye. A cloudy, nitrite-negative specimen may be crystals, mucus, or organisms that do not reduce nitrate. Phenazopyridine (pyridium) turns urine orange and can mask pad colors—do not force a read the IFU says is unreadable.

Quality control. Run the manufacturer’s UA controls at the frequency the IFU and SOP require. Do not use leftover patient urine as homemade QC (that modification defaults the method to high complexity—Chapter 5). Check strip-bottle dating, cap the bottle immediately (pads are humidity-sensitive), and never combine leftover strips from two bottles.

Timing of reads and runover

The IFU assigns seconds, not “when it looks done.” Leukocyte esterase is often the longest visual pad (commonly about 2 minutes on classic Multistix-style inserts); glucose, bilirubin, and several others are shorter. If you use a waived reader, you use its timing, calibration, and QC as cleared. Reading after the stop time is a modification. So is diluting the urine so a viscous specimen “flows nicer.”

Runover is excess urine flooding from one pad onto the next so chemicals mix. Acid from an adjacent pad can distort protein; leftover bleach or strong oxidizers on the container can false-positive blood or glucose. Technique:

• Dip briefly to wet all pads; do not soak.
• Drag the edge along the container rim.
• Blot the edge of the strip on absorbent paper.
• Hold the strip level (or seat it in the reader) so urine does not cascade down the pads.
• Do not lay a dripping strip face-down on the color chart.
• Compare each pad at its time; do not read the whole strip at 30 seconds because you are busy.

Confirmatory tablet and precipitation tests — follow the IFU

Some positives still need a second method. These are confirmatory tests in AMT language. Use them only when the current IFU and SOP still list them.

• Ictotest (tablet diazonium method) is a classic, more sensitive and specific confirmation for urine bilirubin than the strip pad. Follow the current tablet IFU for number of drops, mat, and time.
• Sulfosalicylic acid (SSA) precipitation can detect proteins the albumin-biased strip misses (including some globulins and Bence Jones proteins). Interpret turbidity against the SOP chart. SSA is not a dipstick, and boric-acid aliquots are often the wrong matrix.
• Clinitest (copper-reduction tablet) historically detected reducing substances, including glucose and galactose—the reason pediatric laboratories used it when the glucose oxidase pad was negative but a reducing sugar might still be present. Many laboratories have retired Clinitest: tablets are caustic, the reaction boils, and commercial availability has collapsed. If your SOP still lists it, follow that IFU and the chemical-hygiene rules. If it does not, do not improvise Benedict’s solution at the bench. A CMLA does not independently invent a galactosemia workup.
• Acetest tablets historically confirmed ketones. Same rule: current IFU or not at all.

Do not substitute a second dip for a required confirmatory tablet. Do not use an expired Clinitest “because we still have a few.” Off-label confirmatory recipes default to high complexity (Chapter 5).

What waived UA is not

Do not report a dipstick as culture. Leukocyte esterase and nitrite support a UTI screen. They do not identify the organism, do not give a colony count, and do not generate a susceptibility panel. C&S is a microbiology order with a clean-catch (or catheter) specimen. A positive strip may prompt the provider to add culture; it does not let you type an organism and a drug list from a pad.

Waived urine hCG remains Chapter 12: qualitative cassette, labeled specimen type, read window, control line. First-morning urine is preferred for hCG because it is more concentrated; that preference does not turn the chemistry strip into a pregnancy test.

Automated nonwaived microscopy analyzers and manual sediment identification are moderate-complexity work. Perform them only when the laboratory’s CLIA certificate, SOP, and your competency assessment say you may (Section 14.3). A Certificate of Waiver site that only dips strips does not become a microscopy laboratory because you found a scope in a closet.

In practice

You receive a labeled random cup, 45 minutes old, for waived UA. You mix, dip without runover, time the pads with the IFU or waived reader, record color and clarity, and note leukocyte esterase moderate and nitrite positive. You do not write “positive C&S.” You do not add Clinitest because the glucose pad is negative in an adult with no SOP for reducing substances. You dispose of the strip and leftover urine as biohazard. If culture is also ordered, you follow the sterile-cup or boric-acid pathway from Chapter 9 instead of dipping that preservative tube.

Exam traps

• Reading every pad at 30 seconds, or waiting “until the color looks real.”
• Allowing runover, then trusting protein and pH.
• Dipping a refrigerated unmixed cup, or a boric-acid C&S aliquot.
• Reporting nitrite or leukocyte esterase as C&S.
• Using leftover patient urine as QC, or expired Clinitest as a pediatric screen.
• Calling a urine hCG cassette a tenth dipstick pad.

Keep the method waived by matching specimen, strip, clock, and IFU—and keep culture in the microbiology column.