Chemical Examination of Urine: pH and Protein Flashcards
major types of reagent strips used:
- Multistix (Bayer)
- Chemstrip (Roche-Boehringer Mannheim Diagnostics)
reagent strips be stored at:
room temperature below 30°C (but never refrigerated)
________ a frequent constituent of renal calculi, precipitates primarily in acidic and not alkaline urine.
calcium oxalate
Maintaining acidic urine can be valuable in treating
UTIs caused by urea-splitting organisms
a color change from red to yellow in the pH range 4 to 6
Methyl red
turns from yellow to blue in the
range of 6 to 9
Bromthymol blue
Sources of error/interference
No known interfering substances
Runover from adjacent pads
Old specimens
Bacterial growth
Does normal urine contain very little protein? usually?
less than 10 mg/dL or 100 mg per 24 hours is excreted
the major serum protein found in normal urine.
albumin
produced by the renal tubular epithelial cells; and proteins from prostatic, seminal, and vaginal secretions. a glycoprotein, is produced routinely in the ascending loop of Henle
Tamm-Horsfall protein (THP), also known as
uromodulin,
Clinical proteinuria is indicated at
30 mg/dL or greater (300 mg/L)
3 major categories of proteinuria:
- prerenal
- renal
- postrenal
caused by conditions affecting the plasma before it reaches the kidney and therefore is not indicative of actual renal disease.
Prerenal Proteinuria
increased levels of low-molecular weight plasma proteins, such as:
hemoglobin, myoglobin, and
the acute-phase reactants
A primary example of proteinuria due to increased levels of serum protein is the excretion of
Bence Jones protein by people
with multiple myeloma
perform Solubility Test to confirm kani tong i-boil ang urine unya if naay coagulation or precipitation tas mag dissolve sa 100 C
si Bence Jones, abnormal protein man ni
associated with true renal disease may be the result of damage to the glomerular membrane or tubular dysfunction.
Renal Proteinuria
Additional parameters:
- ascorbic acid
- microalbumin
- creatinine
- calcium
Improper technique includes:
a. unmixed specimen (sediments settle at the bottom and cannot be detected)
b. allowing the strip to remain in urine for an extended period of time
c. performing the reagent strip technique immediately after refrigeration (should be at RT)
Urine Foam Shake Test indicates
bubbles indicate the possible presence of protein/bilirubin
if bubbles disappear, normal.
WHITE foam = ↑ protein
YELLOW foam = ↑ bilirubin or false bilirubin (bc of phenazopyridine = multivitamins)
How to perform quality control of reagent strips?
must be checked with (+) and (-) control once every 24hrs or kada start ng shift. pwede rin kapag bagong open ang bottle, or if sus ang result or dili shoar na ok ang strip
so pag positive, dapat abnormal results
pag negative syempre normal
pag buang buang ang result or erroneous dahil yan sa
a. interference ng oxidizing or reducing agents
1. ascorbic acid
2. formalin
3. detergents
b. pwede pud technical carelessness kay tanga man si medtech
c. pag color blind ka
ang pH sa FIRST MORNING SPECIMEN kay?
5.0-6.0 acidic na pero maging alkaline pagtapos mo kain pero kay self-limiting man siya so mubalik ra pud sa normal if gikan alkaline.
ngano mag alkaline man? kay naa may alkaline tide in which si parietal cells mag release ng HCl exchange kay bicarbonate unya musulod siya sa intestine tas mafilter sa urine kaya maging alkaline
ang pH sa RANDOM SPECIMEN kay?
4.5-8.0
pag 9.0 nana, hala kabalaka na kay murag gi tamper nana or possible old specimen ang gihatag saimo
ang pH sa BLOOD kay?
7.35-7.45
pH has no normal values kay ngano man?
- acid-base content of the blood
- patient’s renal function
- UTI (oh noesz muinom siyag cranberry juice mahimong acidic iyang ihi)
- dietary intake (pwede rapud same sa taas)
- age of the specimen (kay lagi basig old na specimen ba)
unsay reason diay ngano acidic imong urine?
- hala basig naa kay DIABETES MELLITUS
- or gutom ka? mag ↑ imong ketone bodies ana if you’re starving (wow)
- high PROTEIN diet (sagana sa beef)
- i cranberry juice mo ean
unsay reason diay ngano alkaline imong urine?
- renal tubular acidosis daw ana si kuan
- Vegetarian diet (si alka mukaon ug gulay)
- paghumag kaon lagi alkaline imong ihi
- vomiting (yuck)
- old specimen (usab usab) ge unsay pH?
what is the principle of the reagent strip reactions of pH?
syempre double indicator system kay duha man ang reagent vogo
unsa na reagent?
1. methyl red = red → yellow (4.0-6.0)
2. bromthymol blue = yellow → blue (6.0-9.0)
ngano duha? kay wala may normal value lagi kazabot? need daghan variations sa color
what parameter is most indicative of renal disease?
protein = since it should not be detected in the urine
pero sometimes kay pag mag exercise ka or dugay na kayka mutindog, musaka gyud na imong protein (wowza)
Normal protein in the urine:
<100mg/dL per day
since proteins are low molecular weight serum proteins that are filtered in the glomerulus, what is the molecular weight of albumin?
69,000 kDa
ang makasulod sa glomerulus ra kay 70,000 kDa !!!! remember
so makasulod si albumin or dili???
answer: oo pero dili
ngANO????? oo kay sakto raman siya diba 69 gani pero dili kay naa may shield of negativity (bawal pag negative ferson)
major protein found which has low molecular weight
ALBUMIN mameh
other proteins kay:
1. serum & tubular microglobulins
2. Tamm-Horsfall (by: tubules)
3. proteins from prostatic, seminal, and vaginal secretions
proteinuria can also be seen in
- strenuous exercise (tindog dugay)
- dehydration (tindog na gani kag dugay, uhaw pa ka)
- hypertension (uhaw na gani kas sgeg tindog mao na ma highblood ka)
sige lang, REVERSIBLE man ni
unsa pay makita sa proteinuria
- pre-eclampsia (sa preggy naay high pressure (hydrostatic) unya magka organ damage
- disorders affecting tubular reabsorption
- Fanconi Syndrome = damage cells sa tubules and PCT. if naay damage, it means walay reabsorption unya ang mga substances kay makita na sa urine kay naa na may mga damage cells sa brush border sa PCT
Benign conditions in proteins may be exposure to:
cold, strenuous exercise, high fever, and dehydration
Orthostatic (Postural) Proteinuria:
benign, frequently seen in young adults in vertical position and mawala if naka horizontal position
difference between clinical proteinuria and orthostatic proteinuria
CLINICAL PROTEINURIA = naay problem sa tubules and glomerulus
(+) 1st morning and after standing for 2hrs
ORTHOSTATIC PROTEINURIA = wala man kaayo
(-) 1st morning and (+) after standing for 2hrs
microalbuminuria:
only small amount of protein is excreted by patients with DM and can detected in the onset of renal complications & progression of renal disease
Test for microalbuminuria?
MICRAL TEST which employs “antibody-enzyme conjugate”
sensitivity: 1-10 mg/dL
Tubular proteinuria is:
meaning ani, ang mga na filter na albumin kay dili na siya i-absorb (like: Fanconi Syndrome, toxic agents, viral infections)
uNSA MAN NING POST-RENAL PROTEINURIA?
kani tong mga proteins na maka pass through sa lower urinary tract (ureter, bladder, urethra, prostate, & vagina)
theres a production of exudates in bacterial/fungal infections, naa pud blood due to menstrual contamination (contains protein) or prostatic fluid ug large amount of spermatozoa
unsay reagent strip reaction principle sa protein????????????
PROTEIN ERROR OF INDICATORS!
ngano error ang tawag? kay ang protein prone man nis error
color change should be bc of the indicators but instead, protein itself changes the colors
Multistix = tetrabromphenol blue
Chemstrip = tetrachlorophenol tetrabromosulfonphthalein
reaction interference of protein?
- major source would be the highly buffered alkaline urine since ma-override niya ang acid buffer system
- allowing the urine to come in contact with reagent pad for prolonged period (would cause runover which results to false reactions)
- highly pigmented urine & contamination of container = false positive reading
test that detects protein in the urine?
Sulfosalicylic Acid Precipitation Test (SSA)
(can also be a confirmatory in some certain situations)
test that detects protein in the urine?
Sulfosalicylic Acid Precipitation Test (SSA)
(can also be a confirmatory in certain situations but may not be relevant to current lab practice)
reagent for SSA?
3% SSA reagent (Exton’s reagent)
+ 3mL centrifuged urine
if you’re reading this, please MEMORIZE SSA grading
flocculation = solid particles
flocculants = combination of protein & Exton’s reagent/SSA
granulation = small particles
