Laboratory Backup

Rationale

Assessment of adequacy of dialysis, nutritional status, bone mineral disorders, and anemia and monitoring for infections all require frequent laboratory investigations. As various biochemical and serological parameters are dependent on the methodology used and the standardization and calibration of equipment, widespread interlaboratory variation may be observed. It is, therefore, necessary for a unit performing HD to have access to a laboratory with reliable and reproducible results and to establish protocols of investigations for patients dialyzing with them. Some of the basic protocols and requirements of the laboratory for a HD unit are laid out in the following guidelines. Table 1 provides a list of the investigations to be routinely undertaken, while Table 2 lists the investigations essential to screen for blood borne viral infections.

Table 1.

Investigations recommended for patients on maintenance hemodialysis

Parameter	What to check	Remark
Blood urea	Once a month	3 readings, 2 pre- and 1 post-HD
Serum creatinine	Once a month	-
Serum sodium	Once a month	-
Serum potassium	Once a month	-
Kt/V	Once a month	More frequently noncomplaint patients, problems in delivery of HD such as poor blood flow, clotting of dialyzer, delivered dose is slightly frequent from the prescribed one, and recent modification of dose
Hb	Once a month	-
Platelet count	Once a month	Once in 2 weeks if HIT is suspected
Total leukocyte count	Once a month	-
ESR	Once a month	-
Serum calcium	Once a month if the patient is on calcitriol/doxercalciferol/paricalcitol	Once a week when cinacalcet was started for SHPT
Serum phosphorus	Once a month if the patient is on calcitriol/doxercalciferol/paricalcitol	Once a week when cinacalcet was started for SHPT
PTH	Once a month	Once a month when being treated for SHPT
Serum uric acid	Once a month	-
Serum proteins - albumin	Once in 3 months	-
Serum alkaline phosphotase	Once in 6 months	-
Iron studies	Once a month if patients not attained target Hb, on EPO, not receiving iron Once in 3 months if patients not attained target Hb, on EPO, receiving iron Once in 3 months if patients has attained target Hb, on EPO
X-ray chest PA ECG Cardiac Echo	Initially at the start of HD and once in 6 months	-

SHPT: Secondary hyperparathyroidism, Hb: Hemoglobin, HIT: Heparin-induced thrombocytopenia, EPO: Erythropoietin, HD: Hemodialysis, PA: Posteroanterior, ECG: Electrocardiography, Kt/V: Kinetic urea modeling, ESR: Erythrocyte sedimentation rate, PTH: Parathyroid hormone

Table 2.

Guidelines for testing for hepatitis B virus and hepatitis C virus in hemodialysis patients (where universal precautions are strictly followed)

Patient status	On admission	Monthly	Semi-annual	Annual
All patients	HbsAg, Anti-HBc, Anti-Hbs, Anti-HCV, ALT anti-HCV in HD units with a low prevalence of HCV, initial testing with EIA (if positive, followed by NAT) should be considered. In HD units with a high prevalence of HCV, initial testing with NAT should be considered	-	-	-
HBV susceptible like nonresponders to vaccine	-	HbsAg screening should be repeated every 3-6 months once on HD depending on the prevalence of HBV infection in the unit	-	-
Anti-Hbs positive (>10 mIU/mL), anti-HBc negative	Once a year with booster doses as appropriate	-	-
Anti-HBs and anti-HBc positive	-	-	No additional testing needed
Anti-HCV negative	-	ALT	Anti-HCV For patients on HD therapy who test negative for HCV, retesting every 6 to 12 months with EIA should be considered. Testing for HCV with NAT should be performed for HD patients with unexplained abnormal ALTs. If a new HCV infection in an HD unit is suspected to be nosocomial, testing with NAT should be performed in all patients who may have been exposed. Repeated testing with NAT is suggested within 2-12 weeks in initially NAT-negative patients. Screening should be repeated at least every 6 months once on HD. HCV screening should include an ELISA assay and a confirmatory testing with a more specific assay (RIBA)
HIV	Screening for HIV infection should be done in all patients starting HD or transferring from another unit after getting informed consent. Once on routine HD, screening is not recommended

HBV: Hepatitis B virus, HCV: Hepatitis C virus, EIA: Enzyme immunoassay, NAT: Nucleic acid testing, HD: Hemodialysis, ALT: Alanine transaminase, RIBA: Recombinant ImmunoBlot Assay, ELISA: Enzyme-linked immunosorbent assay

Description

Most of the HD units are located in large hospitals and the hospitals have clinical, biochemical, and microbiology facilities attached to them. Usually, imaging facilities are also available with these hospitals. A “stand-alone” HD center may not have an attached laboratory or an imaging facility.

We suggest that in either case, a laboratory with equipment for carrying out tests required for monitoring the management of patients on maintenance HD is essential.

We recommend that the following equipment required for investigations be available in the laboratory where testing is carried out:

1. Biochemistry

   1. Semi autoanalyzer/bench top autoanalyzer
   2. Electrolyte analyzer (ion selective electrode)
   3. Semi autocoagulation analyzer

2. Imaging facility

• 500 mA X-ray

• Ultrasound, echocardiography, and Doppler